Part of the problem with ECC, is that a certain CPU vendor declared that laptop, desktop and low end servers did not need ECC. This means people improvising servers have fewer choices.
I do agree that ECC is highly desirable. But, my desktop, laptops, and miniature media server don't support ECC. And yes, I use ZFS, mirrored OS pools and either mirrored data pools, or in the case of the miniature media server, striped data pool. (For more storage because it's mostly static and I have good backups.)
The frustrating thing about ECC memory, is that with higher densities, both die path size shrinkages and more cells, we have a much higher chance of bit flips than any time before.
In fact, I would prefer to see double bit detect and correction, and triple bit detect ECC memory. DDR5's internal ECC is okay for what it is. However, I'd want to see 16 bits exposed externally too.