Oh, it’s really simple why this happened:

1. People do not like email-based patch processes.

2. GitHub made everything dead simple, and free. Lots of Open Source projects have flourished because GitHub is both easy to use and makes collaboration across repository painless.

3. Very few people actually care about decentralization. As long as you have a full copy of your repo on your own machines as well as GH, it’s hard to argue you’re gaining anything with decentralization.

4. Most people also don’t want to self host a git server.