You're assuming Apple is going to continue even supporting HFS+ long term. They already convert volumes to APFS opportunistically.
You're assuming Apple is going to continue even supporting HFS+ long term. They already convert volumes to APFS opportunistically.
APFS is generally not appropriate for HDDs, so yeah, I expect they'll keep supporting HFS+ for as long as they keep supporting non-flash storage.
In any case, if the situation changes, I expect there'll be enough lead time for me to adjust my strategy -- the failure scenario is completely different than rotting physical media.