Plastics are so cheap and the paper industry has spent many decades learning how to make different composite blends of paper and plastic to get different characteristics. I had a friend who spent time in that industry and liked to point out how plastics could be in most paper-like products you would see every day. He also emphasized how "actual" paper can be unhealthy due to bleaching and other processing steps that leave byproducts.

I don't know if it's really solved anything, but I switched to loose leaf teas with a stainless steel "tea ball" for individual cups. Now I can instead wonder what metals the global supply chain decided to actually use in that product. ;-)