One big issue is using single-stream recycling where everything goes into the same bin and it’s the responsibility of the recycler to separate them all back to individual types. That is simply way too complicated and expensive for most of the materials so they just don’t do it, and most of it simply goes into a landfill.

When the sorting is done by the consumer as it’s done for example here in Finland where we recycle more than 90% of bottles and separate everything else into their own bins, you end up with much higher recycling rates. We do still lack enough processing capacity to deal with it all so a lot of it is burned for energy, but at least essentially nothing is going to a landfill any more.