We had a bad side effect here in Ontario (Canada) not so long ago. The LCBO (liquor store) was using plant-based "plastic" biodegradable bags. Then our crack- and alcohol- addicted mayor (Rob Ford) passed a bylaw in Toronto so stores had to charge 5 cents per plastic bag. That sounds like a good idea, except that the biodegradable plant-based bags were still considered plastic. So, the liquor store stopped using them entirely, and opted to stick to standard brown paper bags, which haven't nearly the strength of the plant-based bags.

Eventually that law was given up because it was hugely unsuccessful - people didn't even slow their usage of plastic bags, and so a lot of resentment developed since no environmental impact was to be found, and stores were clearly happy to profit off of using super-cheap low-quality plastic bags they still charge 5 cents for.

Several years later, still nobody is providing or using the biodegradable plant-based bags. People seem happier, or at least numbed to the idea of paying extra for plastic bags, than either carrying their own bags, or turning to other solutions.

BTW: The lcbo bags were made out of the same plant-based material as used in bio-degradable cutlery, which likewise has pretty much failed to replace single-use plastic ones. For no reason, since there is clearly no shortage of plant-based material from which to manufacture them.

I believe there to be a serious marketing problem when it comes to already existing solutions.