Migrating a very large subversion repo to git is not trivial. The KDE team spent a lot of time just developing the tools required to do it https://github.com/svn-all-fast-export/svn2git
But even with those tools it’s still quite a process. If there are lots of large binary assets (often the reason for using centralized to begin with) the adoption of Git-LFS, GVFS etc is a time consuming process.
I have waited years just for the tools to mature (LFS etc) and now I expect to spend a few weeks at least, migrating our single svn repo to git.
Switching from SourceForge should be a no brainer though, completely agree with that - even for projects that stay on SVN.
KDE was a special case because we wanted to split a monorepo into one repo per application at the same time, yet retain as much history as possible (including across restructurings of the source tree). Also, the massive size of the monorepo (about 1.5 million revisions) made it infeasible to use the standard tooling of git-svn to do it.
Most projects will not have these problems. At work, I migrated a rather large application (~500k LOC) from SVN to Git while retaining the entire history, with the standard tooling (`git svn clone && git push`, basically).
Migrating it using git svn is a couple of days (and annoying when it stops half way because of some issue) At least with svn2git we can test-convert including lfs migration in just a couple of hours.
See the referenced article.....
That, and the fact that GitHub is a closed source backend under control of a corporation that's accountable to no one.
And I have no problem with a project not wanting to use github for this reason either - everyone is free to roll their own, or use something else, but the point stands that SF isn't exactly a better alternative for those reasons and most small projects should just end up on github because that's where a lot of OSS development has coalesced anyway and at least github has a been a decent steward providing free OSS project hosting.
1. "and the fact that GitHub is a closed source backend under control of a corporation that's accountable to no one"