I have the feeling that Git winning the war hinges heavily on GitHub being the way to do open source projects, and that is changing given the sad state of GitHub.
Another contender is Jujutsu (jj) which allows you to use jj as frontend and use Git as the backend (with the potential to support any backend, e.g. Google's proprietary Piper), with the best ergonomic and the widest availability of hosting solutions.
> I have the feeling that Git winning the war hinges heavily on GitHub being the way to do open source projects
Nah. At the time BitBucket was the better way to do open source projects, and they were Mercurial-first. But eventually they had to add Git support because there was so much demand.
I’ve recently switched to jj and it is truly amazing. It too about a week for me to “get it”. The tool is amazing but I think there’s way too much emphasis on what it does/allows rather than what benefits it brings to your workflow. If they get that marketing right I could see it growing. If not, I’ll keep using it