"Plastic recycling sits quite low in the waste hierarchy as a means of reducing plastic waste. It has been advocated since the early 1970s,[11] but due to severe economic and technical challenges, did not impact plastic waste to any significant extent until the late 1980s. The plastics industry has been criticised for lobbying for the expansion of recycling programs, even while industry research showed that most plastic could not be economically recycled and simultaneously increasing the amount of virgin plastic, or plastic that has not been recycled, being produced."
It's pretty much a well known fact. Recycling is extra hard due to the need to separate the plastics and then the molding new plastics requires specific type of plastic molecule. Many plastics are even blends, e.g. ABS + PC, or glass fiber filled ones.
"Plastics" are just so many types, different in all kinds of ways. So separating them and using them in anything sensible doesn't happen often at all.
https://en.m.wikipedia.org/wiki/Plastic_recycling