I agree to a point, one factor that can help mitigate this however is using a quality SSD where it's onboard memory has ECC, I suspect Apple sees the near future of end user computing as gaining ECC for all memory by standard which is something I've wanting for years but games have been played by CPU manufacturers to prevent the use of high end desktop CPUs in server environments by I believe purposely kneecapping them from using ECC memory (citation probably needed here).

I haven't done any serious analysis of Time Machine (or of APFS for that matter), but I think in general Time Machine also only keeps one copy of files. So APFS isn't worse than the existing situation. Arbitrarily keeping multiple copies blows up the disk requirements. You can intentionally keep old copies around in APFS via snapshots, which is what APFS will probably do when implementing Time Machine.

What Apple added for the existing Time Machine on HFS+ was an extension of the Unix concept of hard links to files (where there is only one copy). They added hard links to directories. Generic Unix avoids doing that for a number of reasons.

Isn't is already true that there is one copy to corrupt? The whole idea of using hard-linked trees (a la rsnapshot [1]) presumes that when a file doesn't change, there is only one copy.

[1] http://rsnapshot.org/