See https://github.com/matthiasgoergens/git-snap-fs for my example of read-only access to git via fuse.

I built the original version in Python for a job years ago. But the version above is almost entirely vibe-coded in Rust in a lazy afternoon for fun.

However, I disagree that the filesystem is the right abstraction in general. It works for git, because git is essentially structured like a filesystem already.

More generally, filesystems are roughly equivalent to hierarchical databases, or at most graph databases. And while you can make that work, many collections of data are actually better organised and accessed by other means. See https://www.seas.upenn.edu/~zives/03f/cis550/codd.pdf for an particularly interesting and useful model that has found widespread application and success.