What I do know is that ZFS recently released a feature specifically for the hobbyist/frugal community. The feature allows you to grow an existing RAID array, something a financially sound business would never do. So no customer of anyone supporting ZFS would ever use this, and it took significant effort of ZFS developers to implement this. Not to mention that introducing feature potentially introduces weird behaviour in ZFS that might endanger its (reputation of) stability.

I'm super happy with it, (as my company was not in fact financially sound when we invested in our on-premise storage hardware), but if I was CEO of ZFS I'm not sure I'd sign off on it.