I totally agree with (c) and believe it should be addressed. Plastics need to be collected when they become garbage and reused as building material and if not possible stored properly for next hundred or few hundred years. We need to create proper incentives for that. Reduction of plastic use should of course be encouraged but not at the cost of functionality. So peeled bananas in plastics should be banned, but juice bottles shouldn't be glass.
As for (a) plastic uses up about 6% of oil we dig up so political influence of plastic manufacturers is probably roughly proportional. That explains why we have paper straws while oil extraction and burning continues and increases completely unrestricted. Plastics are just the easiest political target.
And as for (b) making plastic takes less energy than making glass or metal for the same purpose, plastics also are lighter so produce less emissions in transport so if we magically waved away all the plastics our emissions would rise by many percent, not fall. And we can't just not use packaging because the we would waste even more food which would also cause emissions.
It's like with ethanol for cars. In theory it was supposed to save emissions. In practise it caused greater emissions due to land use change for the purpose of growing corn to make methanol.
Probably half of the things we do (my wild guess) to help the environment or emissions specifically actually increases emissions in the end.
It's sad to see that even on HN there is huge representation of mainstream simplistic views that don't recognize complexities of the world and the need for carefulness to not make things worse.