> if you want to convince people to give up Github you should at least be prepared to give an alternative that offers a great deal of feature parity.

These can't both be true. In fact Github is hard to switch away from, because of all the Github features. This is the lock-in. Github then monetizes this by charging for large files (https://docs.github.com/en/repositories/working-with-files/m...), private repos, etc. So the SFC argument is that you should switch away from Github now and get the alternatives to feature parity, to avoid Github getting a monopoly.