As a developer who ditched Github and decided to self-host, there is only one reason. It's not technical difficulties, politics, nor AI. It's Microsoft. Like Apple, Facebook etc, I have a deep loathing for Microsoft and I want to remove as much of it from my life as I am able.
I now run Git on a pi using Gitea and Forgejo. I can now upload files of a size unheard of in GitHub, Claude can make a PR by itself that I can diff, edit, then merge, and even with the mighty power of a single pi 3b+, it feels more responsive.
Microsoft's human rights stain will take decades to wear off (just like Meta, Google, and Amazon).
Microsoft is a mafia that sometimes produces code (poorly).