Plastics are packed with energy. There are already bacteria and fungi taking advantage of that energy source. I think we’ll soon see micro-plastics being “taken care of” by a new ecosystem.

The bacteria will spread like wildfire: the environment is lush with micro-plastics. Things will evolve from there. Perhaps in the future, natural bacterial gene transfers will create plastic-consuming termites.

https://microbewiki.kenyon.edu/index.php/Plastic-eating_Bact...

https://e360.yale.edu/digest/bugs-are-evolving-to-eat-plasti...

Oh, heck, turns out there are plastic-eating caterpillars!

https://www.theatlantic.com/science/archive/2017/04/the-very...

In the dystopian future, we no longer have plastics because it just gets eaten, as useful as building homes from gingerbread.