The idea that we'll get Americans to properly dispose of plastic is not credible to me, without some kind of cultural shift that I don't expect (I'm aware that some other countries, perhaps Germany and Japan, are much more diligent about how you dispose of household waste).

I've observed a number of people who haven't seemed to internalize the current rules about what can be recycled. People especially want to think that thin plastic bags can go in the recycling with everything else. I don't think people are going to move away from single-stream recycling, which appears to be a big part of the problem.