In Europe (yes, generalizing an entire continent) we generally avoid landfills and instead burn anything nontoxic that doesn't go to recycling. It's a great way to produce electricity and have all produced gases in one place where you can filter them. Plastic burns just fine. Obviously we try to recycle it first, but a lot of it still ends up burned. The ash that's left over is used in construction, but plastic doesn't even leave ash.