If it hasn’t already been broken down into microplastics yet and it’s floating around in its whole form, then other organisms that eat fish that size could think it is a fish and then eat it,” Wootton said.

And:

“Since they are quite a thick plastic, it does take quite a while for them to degrade.”

I imagine the people who get takeout sushi and the people who have a bottle of soy sauce in their fridge are largely different groups.

Tbh there's your answer, fix that. Buy some damn soy sauce, they sell it at the most basic stores.

But that doesn't solve the issue for people eating it at a third location, like work, their car, or an unprepared friend's house, can't buy bottles of soy for literally everywhere you go "just in case" and such.

Maybe we still need them for that, but we can also be mindful of our circumstances and prepare/choose appropriately. Would require people to change personally however, so keep waiting lol.

Hell maybe we just make it common for them to sell little 4oz resealable glass bottles of kikkoman at the Chinese spot, then one can still be unprepared and still get the sauce there (though it'd be cheaper if they prepare next time), and whatever sauce isn't used is retainable. Still not perfect since those bottles have plastic tops, but it's something! Maybe make the caps out of hemp plastic for added bonus?

How does it biodegrade though?

Just like disintegrate into tiny plastic molecules that we can no longer see but it's still plastic? Or does it degrade as far as becoming the individual components that made up the plastic and can be recycled and used by things in nature?

Sure, but PLA will eventually biodegrade, unlike things like polypropilene or polyethylene, which are incredibly useful precisely because of their imperviousness.

EDIT: I'm willing to bet that PLA IS biodegradable in home settings if the correct method is used, like the Berkeley method, which produces much higher heat than "heap" methods. The Berkley method can produce compost in under a month, via endothermic processes that generate relatively high heat. All you need at home are the compostable materials, and a roughly 1m cube, which can be made out of pallets, for example.

How to Make Compost in 18 Days Using the Berkeley Hot Composting Method

Regular composting, also known as cold composting, involves placing a variety of organic materials in a compost bin, enclosure, or even just in a large heap, and leaving it there until it breaks do…

^{Deep Green Permaculture}

The caveats you express are somewhat valid, but not totally correct. Printing correctly, with a food safe nozzle, path, and PLA formulation, is entirely possible. Simply printing in single layers, with a properly dialed in printer can eliminate your concerns. Medical items and implants are printed out of PLA, albeit with extreme production controls.

However, printing these single use items would be absolutely un-economical. 3D printing shines in short runs, bespoke items, like replacement part that are out of production, or which are very difficult to manufacture by other methods like injection or machining.

Its true that PLA, in unmodified form, has a much higher modulus than PP or PE, so squishiness is out of the question. What I have mentioned before is that I have bought single serve olive oil in PLA containers. From what I could see, these were injection molded and had a film top made from a plastic I never bothered to identify.

These containers were surprisingly elastic when crushed, not as elastic as other plastics, like PET, PP or PE, but much more than I had come to expect from my experience with the material. I'm going to attribute this to molding vs. extruding.

Good luck relying on informed customers when customers are too busy living their lives to keep track of a billion different reasons for why they shouldn't buy one product over another. Also, these are given out at restaurants. Do you recommend refusing to go to a restaurant if they happen to see this dispenser being included there?

How is making sure millions of people are informed and making the "correct" decision every time a better solution than simply restricting on the supply side?

Portability and cost.

I don't support single use plastics but saying no benefit is just willfully ignorant and causes alternatives to fail for missing the point.