I give you that some of the new features are tied to OS-wide updates, but many of them seems they're not. And if they wanted to, they could still decouple apps

I give you that some of the new features are tied to OS-wide updates, but many of them seems they're not. And if they wanted to, they could still decouple apps from OS updates and if you're on a old OS version and the new app update requires a newer OS, just block that specific update from happening. > Plus of course everything is tested together That makes sense, Apple's QA department seems to be held together with tape for the last decade or so, as every new update seems to break something, so maybe they're trying to make it as easy as possible now in order to recover.