I thought unix was an imperfect implementation of this, and plan 9 was the spiritual next step forward[1] (haven't tried plan 9 much)

also, I've always wondered about "everything is a file" in relation to metadata.

I think eliminating metadata (meta-information about the file) might be a good thing.

MacOS had a lot of infrastructure in the opposite direction wrt metadata, with resource forks[2] and arbitrary/cumbersome . I never liked it. It seemed like information got arbitrarily shoved there and it got further from everything is a file. And stuff got out-of-sync/lost and could break the world.

[1] https://en.wikipedia.org/wiki/Plan_9_from_Bell_Labs

[2] https://en.wikipedia.org/wiki/Resource_fork

The downside of this is that filesystems seem to be a weak point in the Unix and Linux ecosystems. Even with FUSE, trying to mount an non-existent network drive, or access a mounted one that has gone offline can majorly slow down or completely lock up the system.

Unix FS is the best FS!