Well we also ended up with BTRFS raid5/6

I think "mature" is the more correct term. It's not the regulation, it's just that it's been vetted and repeated so many times that it has become rock solid.

This is why I never select cutting edge tech for our company - unless it's part of our area of expertise/innovation.

That's also true. Filesystems do have an advantage of being testable by millions of people, relatively stable from one user to another over the medium term, and at least the experts share their experiences. Also, there are no gaps in the regions that benefit from good filesystems. Regional enforcement means spotty enforcement.

As for expense, the reliability of the filesystem is free up to a certain point. There are system failure modes that have to be covered by hardware and admin expenses, such as decentralized backups (just one example off the top of my head).

File systems are very expensive. Not up front, but instead on failure. Bad/cheap file systems don't last long.