What we should do is transform the materials. Instead of using hydrocarbon polymers we could start off with sugar based polymers. These can be engineered to degrade and there are already plenty of naturally occurring bacteria that eat them. It will mean being satisfied with plastics that go bad and need to be disposed much quicker, but they will could be both recyclable and naturally degrading if we got the science right. Plastic is such a useful technology that it is unlikely we will simply abandon it.
Indeed. I'd think reserve plastic made from oil for important things like medical devices, but where one/we might draw the line is an interesting question.