Nobody seems to have really embraced the truly distributed model of git, where you can expose a local repository via read-only HTTP, and collaborate by pulling from each others' repositories. No pushes.
This would be unwieldy in a corporate environment and for those who don't really grok git, but for a small cadre of experienced developers, this may be a workable model.
Sourcehut _kind of_ pushes for this model. Folks publish their own repositories, and email patches to others. But you can also just email a patch to the author without a Sourcehut account, because email is descentralised.
The Linux kernel and u-boot also follow similar flows.
Honestly, it's incredibly convenient to send a patch via `git send-email -1`, instead of having to create a for, add a remote, push, and then navigate some web-based wizard.
That's how I learned git before GitHub, but it was a pain to configure DNS and port-forwarding when ISP didn't provide static IP.
Radicle doesn’t get enough credit. They’ve created a really excellent take on modern distributed git.