The ease of mind of the current developer is far less important than software not breakly widely for users because previous developers made bad assumptions about version strings.
Making policy to avoid the consequences of prior bad practices does not sound like a recipe for encouraging good practices moving forward. In terms of technical debt, it's like taking out a loan to pay off a credit card. I worry this will just lead to baking in more bad assumptions as developers hurry to get this off their plate.
I wonder why they don't announce a deprecation of the old versioning schema, and give developers time before switching, instead of just doing both at the same time with little to no warning. They've done that with lots of other technical migrations and even then, there is still plenty of controversy–see Catalina 32-bit support. Is there any reason to believe that doing a migration outright is safer, when the stepped approach has already proven difficult?
The least charitable guess I can come up with is that this was a mistake that they can't walk back for technical reasons, so are just fixing forward.
If it were up to me, I'd announce that a future version of macOS will increment the major version and that will be moving to semver/calver/whatever-other-protocol, and do it when the current place name marketing strategy runs its course, as did the cat name marketing strategy. That would also give a few more years to get any major UI/system changes ready to drop for macOS 11. Just my 2¢.
The issue is old software continuing to work without having to be updated.
Giving more "time" solves nothing for all the programs out there that cannot or will not be updated for whatever reason.
This wasn't a mistake on Apple's part, it's just working around bad programming practice by developers. But there's no reason why users should suffer for it.
If they instead didn't move to 11 at all, what would stop working? What is the thing they are rushing to solve before things stop working? I think I'm missing something there.
I agree with users not needing to suffer, I'm not advocating for a hard break here.
Edit to add: is it necessarily a bad thing for unmaintained software to die? Keeping them around sounds like a great way to accumulate security vulnerabilities.
Damned if they do, damned if they don't…if Apple broke all the old software here, people would be up in arms about how they should have added a "legacy mode" for these applications.
The ease of mind of the current developer is far less important than software not breakly widely for users because previous developers made bad assumptions about version strings.