The web is full of people shouting "_____ filesytem doesn't get fragmented!" Apparently they've never let a filesystem get above 70% full or so, especially one

The web is full of people shouting "_____ filesytem doesn't get fragmented!" Apparently they've never let a filesystem get above 70% full or so, especially one on a fileserver that has seen years of daily use by a dozen+ people. I've heard it for HFS, HFS+, XFS, ext3, ext4, etc and every time it was an lie. Every filesystem fragments after regular use unless you have a fuckton of free space. It's pretty hard to justify to one's bosses over-provisioning disk space to enough of a degree to render fragmentation unlikely, and users just expand their data to fit it anyway.