As usual, another example of the Linux echo chamber. It's just one constant inward gaze with that crowd. They learn nothing from anyone, only trial and error.
I don't know that I'd agree. As much as llvm+clang inspired gcc to improve, ZFS seems like a big part of the inspiration for btrfs. I'm not sure that it hits the whole ZFS feature set, but it's probably a step in that direction.
Including the fragmentation experience of the UNIX wars glory days.