> It's to the point that if you read an entire disk 4TB you have a 32% chance of one bit being wrong!
If this were the case, forums would be filled to the brim with ZFS users whinging about how they get CKSUM errors practically every time they scrubbed their pools. They do happen, but nothing like that frequently.
> That means hard disks can no longer be considered reliable devices that return the data written to them
They were never such devices in the first place if you ever valued your data enough to care. Even if your disks are perfect, your cabling, backplanes, IO controllers, drivers or memory probably aren't.