I disagree that full responsibility needs to go on the manufacturer. An undeniable issue with our current system is that consumers expect to throw all plastic in one bin that isn’t the garbage and be done with it. There are lots of different ways to set up responsibility, but on top of production changes plastic “recycling” will need to change significantly from the user perspective. Things like stronger deposit programs would be a bare minimum to start addressing the consumer side (in tandem with measures addressing production of course)

Significant reduction in single use plastics, banning plastic use in certain products (even non-single-use), and a drastic increase in accountability for producers and consumers.

Also remember styrofoam is just extruded polystyrene, which you can find in other common items such as soda cup lids.