Plastic

 https://apnews.com/article/biobased-biodegradable-plastics-climate-compost-838fb5b4619e5020e3c01157a312a5d8
The article doesn't mention comparable cost nor the ubiquitous plastic bag.

You're right. The AP piece is largely about the technology and environmental promise of PHAs, but it mostly sidesteps the two questions that determine whether they become more than a niche product:

    What do they cost compared with ordinary plastics?

    Can they replace the humble plastic shopping bag?

On cost, the answer today appears to be: still significantly more expensive. Estimates vary by material and location, but biodegradable plastics such as PLA, PHA, and PBAT are often roughly 2–3 times the cost of conventional polyethylene or polypropylene plastics. One recent review put biodegradable plastics at roughly $2,000–7,000 per ton versus $1,000–2,000 per ton for common plastics. Another study found biodegradable bags costing well over twice as much as conventional plastic bags.

That doesn't mean they will always remain expensive. The history of manufacturing is full of products that began as luxury items and became commodities once production scaled. But cost remains one of the principal barriers to widespread adoption.

As for plastic bags, technically the answer is yes: biodegradable and compostable bags already exist. The catch is that many require industrial composting facilities and may not break down as advertised if they simply end up in ordinary landfills. Several studies and reviews point out that infrastructure is as important as the material itself.

The article also skirts another uncomfortable question: if a compostable bag is used once and then discarded, have we really solved the problem or merely substituted one disposable item for another? Some environmental analysts argue that reducing single-use consumption and increasing reuse may ultimately matter more than switching polymers.

My guess is that the AP reporter avoided cost because it muddies the narrative. A story about "scientists make plastic from sugar that disappears in six months" is straightforward. A story that continues "...but it costs two or three times as much and requires special waste handling" is less dramatic, though arguably more useful for understanding whether the technology can conquer the market.

The plastic bag is actually a very good test case. It is one of the cheapest manufactured products humans make. Replacing a disposable fork used in a coffee shop is relatively easy; replacing billions of ultra-cheap grocery bags without multiplying costs is much harder. That economic reality is probably why the article focused on cutlery and specialty packaging rather than shopping bags.

Plastic runs from chairs and tables to spray bottles and other containers, all used over and over.  The bags around here (my standing instructions are to buy things in glass whenever the alternative is present) do get reused, but only a few times.  Hence they produce far more volume of plastic than the items in the article.

That's actually very close to how many people intuitively think it ought to work.

A deposit system says, in effect, "We charge everyone in advance because we assume some people won't return the container." The consumer gets their own money back later if they do the right thing.

Your alternative is more like a scrap-metal market. Nobody pays a deposit when buying an old refrigerator or aluminum can. Instead, someone collects it because it has value, and a recycler pays for it. The transaction occurs only when the item enters the recovery stream.

The difficulty is economic rather than administrative. An aluminum can contains enough valuable metal that it can support a recycling industry. A glass bottle or plastic container often doesn't. The cost of collecting, transporting, sorting, washing, and processing may exceed the value of the recovered material.

The deposit solves that by creating an artificial value. A bottle worth perhaps one cent as material suddenly has ten or twenty cents attached to it, making recovery worthwhile.

What I find attractive about your idea is that it separates retailing from recycling. The grocery store's business is selling groceries, not acting as a bottle depot. Many consumers dislike hauling empties back to stores, and merchants often dislike handling them.

Historically there were systems rather like what you describe. Rag-and-bone men, junk dealers, scrap merchants, bottle collectors—independent businesses that bought discarded materials because there was enough value in them to make a profit. In many developing countries that still exists. One sees people collecting bottles, cardboard, metals, and plastics because there is a market for them.

The challenge is that the least valuable and most troublesome items—the thin plastic bag from your earlier example is a perfect case—often don't have enough intrinsic value to support such a market. If a kilogram of plastic bags is worth only a small amount, someone has to bear the collection cost.

So there are three broad models:

    Deposit system — consumers prepay and reclaim their money.

    Tax-funded collection — society pays through taxes or waste fees.

    Market purchase — recyclers buy returned material because it is valuable enough.

The third is elegant when it works because it aligns incentives naturally. The first exists largely because, for many containers, the material itself isn't valuable enough to support the third.

One irony is that if legislatures standardized bottles—as we were discussing earlier—the economics of your preferred approach might improve dramatically. A recycler receiving ten thousand identical reusable glass bottles has a much easier and more profitable business than one receiving ten thousand different shapes and sizes. The standardization that reduces consumer choice can increase the residual value of the container, making market-based recovery more feasible.

So I suspect your instinct is pointing toward something real: not necessarily "abolish deposits," but "make the recovered item valuable enough that people want to buy it." That's generally the most self-sustaining arrangement whenever it can be achieved.

The containers my coffee and tea comes to me in are former jars of instant coffee one of the other tenants here buys and then gives to the landlady.  Jar and lid both being reused.  My spices, locally grown and sold bulk, are dried and ground and come to me in the same jars.

That's a lovely example of something that economists sometimes call a reuse cascade.

The jar was originally designed for one purpose—holding instant coffee. But instead of becoming waste after its first use, it enters a local informal system:

    Coffee arrives in the jar.

    The jar is emptied.

    Another tenant passes it to the landlady.

    The landlady uses it to package tea, coffee, or spices.

    You use the contents and may pass the jar on again.

No legislation, deposits, recycling centers, or environmental campaigns are required. The jar has enough practical value that people keep finding uses for it.

What's striking is that the lid survives too. Often the limiting factor in reuse is not the container but the closure. A glass jar is nearly immortal in ordinary household use, but a damaged or missing lid can end its useful life. Having both jar and lid reused greatly increases the value of the system.

In many ways, this resembles how containers were treated for most of human history. People did not think of a jar, bottle, sack, or box as something to throw away. It was a useful object in its own right. Only when mass production made containers extraordinarily cheap did "single use" become normal.

Your story also illustrates the advantage of local reuse over recycling. Recycling usually involves collection, transport, sorting, processing, remanufacture, and redistribution. Reusing the jar for spices skips all those steps. The most environmentally friendly container is often not the one that is recycled most efficiently but the one that never enters the waste stream at all.

And there is a certain practicality to the arrangement. A transparent glass jar is excellent for tea and spices. You can see the contents, it doesn't absorb odors, it is easy to clean, and in Cambodia's climate it keeps insects and moisture out if the lid seals properly.

What you describe sounds less like a formal environmental program and more like the sort of small-scale, commonsense thrift that used to be commonplace. The jar remains useful, so it continues circulating. No one needs a theory of sustainability to make that happen. They simply recognize that a perfectly good jar is still a perfectly good jar.

Not so elegant, but also fine glasses.

Quite. An instant coffee jar may never have been intended to grace a banquet table, but it often makes a perfectly serviceable drinking glass.

There is a certain honesty to such objects. A purpose-made wine glass announces itself as a wine glass. A reused coffee jar says, "I was one thing, now I am another." And from a practical standpoint, many of those jars are sturdy, hold a comfortable amount of liquid, and survive rough handling better than delicate stemware.

Historically this sort of repurposing was common. Mason jars became drinking glasses, jam jars became storage containers, tins became tool holders, wooden crates became furniture. People tended to see the object first and its original purpose second.

One thing I've noticed is that when people reuse containers regularly, they begin to judge them differently. A consumer might choose a jarred product not because of what's inside but because the jar will be useful afterward. The container acquires a second value beyond its original contents.

Your coffee jars seem to have achieved a kind of local promotion: first coffee container, then spice jar, tea jar, storage jar, and occasionally drinking glass. Not glamorous, perhaps, but getting far more service than the manufacturer ever expected when it left the factory.