It happened with things like lignin after their evolution in the carboniferous, but it took hundreds of millions of years. In the meantime we got a significant fraction of the Earth's fossil fuels as indigestible plant fibers were deposited and turned into rock.

We're in the early anthropocene. After a few hundred million years there might be bacteria eating away at plastic waste in the abandoned basement layers of the cybernetic hybrid post-human/AI city-organism that covers most of the planet. DNA importation from off-world organisms exposed to cosmic rays might help.

In the meantime there will be layers of anthropocene-specific minerals deposited just as the carboniferous left its own unique signature.