It's hypothesized that a similar story played out for lignin, leading to the majority of the world's coal deposits. In the Carboniferous period ~300 million years ago, plants evolved a class of organic polymers called lignins which were difficult to break down. This lead to a massive accumulation of dead plant matter that nothing could digest. It only ended when fungi evolved the ability to break down lignin.

See the section on coal formation here https://en.wikipedia.org/wiki/Carboniferous