>>276033634
There are numerous different types of consumer plastics. Some aren't recyclable at all, some are but only inefficiently. IIRC it's only PET bottles that are an energy win, and depending on the process they can only be "downcycled" into a less stingent industrial use, not used to make more bottles. The difficulty of sorting all these plastics makes it not cost- or energy- efficient in many cases.

As far as landfill space goes, it really is a non-issue. Landfills are small, and America is massive. Really, unbelievably huge, and empty. Once a landfill is full, it gets capped and landscaped and you can't really tell it was ever there. Landfill space is only really an issue for the city budget of huge cities like New York, where the city recycles because it's cheaper for them than to pay the rates landfills in New Jersey would charge.