My solution is RAIDZ5 and storing the backup on LTO6 tape with parity/erasure code. I think the fact that scrub times take 24 hours even on 16TB drives is already over the safety margin. If a drive failure happens, the first thing I'll do to run a manual diff backup which should take a fraction of the time and then run the ZFS resilver.
I'm beginning to see why SSD RAID is being considered now. My guess for HDDs in enterprise is that a RAID 15 (I made this up) would be considered. What I mean is data is stored on two identical servers each running RAID5 or 6. Off the shelf solutions like Gluster exist and that seems to be gaining traction at least according to Linus Tech Tips.
I suppose one interpretation is that companies can no longer use "buy" and will have to use "rent" for that transaction.