Most "forks" on github etc are not about forking projects, but more about having a source for pull requests to the main repo.
Also people keep "forks" simply as backup in case the main repo vanishes.
(I keep my own "forks" of quite a few projects just for simple modifications, mostly related to meta-data (tagging, packaging etc) and not so much because of actual code changes, these "forks" automatically pull from upstream regularly, and packages are built via gitlab-ci when I tag something for production ready.)