git itself doesn't support a decentralized push as far as I know, or rather that decentralized hosting infrastructure hasn't been built to seamlessly work with git.

Yes it does, you can either push to multiple remotes individually, or setup multiple pushurls for a single remote.

I'm a blockchain skeptic with the best of them, but this does not solve the problem GP is describing. Yes, git supports multiple remotes, but there is no durable, decentralized hosting infrastructure for arbitrary repos that I am familiar with.

Unless I misunderstand git-ssb does this.