Note that ext4 is damn old and thus also not as performant as more modern ones like btrfs or bcachefs
This is not true. BTRFS has more features but ext4 is very performant. They're both similar enough that I promise you that you wouldn't notice unless you had some very specific use-case that needed to be performance tuned.
What do you think "being old" has to do with performance?
BTRFS seems to be better at multithreading, being outperformed by F2FS (which I forgot to mention, it is used on Android and I would call that damn stable).
Actually, F2FS seems to be a really good replacement for EXT4, being top in most tests, while having no journaling, while BTRFS in fact worked pretty badly!
It is 16 years ago, that's pretty old in terms of technology.
It's also an evolution of ex3 and ext2, and ext if you want to consider it's very short lifetime. In fact, the lead developer stated in 2008 that it was meant as a stop gap, as it's based on old technology with some new features, and that BTRFS was the future.
Hmm ? Linux kernel is way older than ext4. And before ext4 there was ext3 and ext2. Linux users also have the choice of using XFS file system and for IT persons working for corporations XFS can have some advantages. Let's see, XFS was born in 1993.
more modern ones like btrfs or bcachefs
Years ago I thought that bcachecfs looked interesting but last thing I read about it this year was not very promising regarding reliability. Not sure whether it was in comments on Lemmy but here I found something from Linus himself : https://en.wikipedia.org/wiki/Bcachefs#Stability
Yeah, bcachefs is still very very young, and not ready for much of anything beyond tinkering. But I'm definitely excited to have a native filesystem that's designed with tiers in mind.