Sometime in the far-away future chunks of plastic will be displayed in museums like ancient artifacts. This may seem odd to you. But remember plastic doesn’t decompose and won’t have the pleasure of being eaten by worms and micro-organisms.
Plastic will sit there forever. The people of the future will be baffled by objects like dollar-store spatulas and Nerf guns. They will be information plaques made of Iron that will carry helpful inscriptions that attempt to decipher the meaning of these bizarre artifacts. They will get it wrong of course. How can the future understand a past that doesn’t understand itself?