Let's face it: at this point macOS version numbers are a marketing tool, and not much more. It's only 2 major releases ago that a "x.y" release *would* have been considered "major".
I don't think that's particularly relevant. It was pretty clear that between 10.0 and 10.15, the second number was the "major" version for all intents and purposes, and now it's the first number.
But I really did think that since it was in Monterrey, it was going to stick around until at least macOS 13.