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.