btrfs was available in the Linux kernel in 2009, but didn't see production release in the tinkerer-friendly distros until 2012 and in an enterprise distro until 2015. These things take time: filesystems need to be absolutely bulletproof, especially in the consumer space where (unlike Linux) most users will have no idea what to do if something goes wrong. I'd say Microsoft is still on schedule.
Just yesterday, I did my first Linux installation with ZFS as the root/boot filesystem (Ubuntu 16.04). This is after using it as the default filesystem on my FreeBSD systems for several years, and being very happy with it.
I've used Btrfs many times since the start, and been burned by dataloss-causing bugs each and every time, so I'm quite cautious about using or recommending it. I still have concerns about its stability and production-readiness. If in doubt, I'd stick with ext4.
I've had F2FS on an Android tablet for many years. Resurrected it. However I'm running Debian on my laptop and I'm scared to try f2fs on
/ Because i get warnings about it being not fully supported "yet" i would love to have an SSD optimized FS on Linux. Since AAPL will open source the release version, is it conceivable that AFS could replace ext4 as the default Linux FS?
Without getting stability and reliability correct don't bother with the other features. What good is it if the filesystem handles oodles of drives if none of them have any of the data you put on them?