@DougS
Upvoted your post, can't agree with your finding though. The Linux kernel has no problem supporting many different fs, like ext* or btrfs etc. It's a pain to mount it automatically on many android devices other than Nexuses. I got to manually mount an ext2 sd card on my rooted noname device. As I understand the custom OEM mount scripts (various subs for fstab) are merely impossible to edit. In my case it's HTC that wrote it.
So, I guess, the only Google's fault here as in many other areas was not to enforce clear standards onto the OEMs