The transition happened so gradually that we ended up here without a lot of discussion, which is why the discussion is happening now.
This is not to suggest we should remove this capability from macOS/Windows but I wouldn’t call it a regression.
I bet you’re right about the motivation for this silly outrage: People claim the iPhone is a PC because they wish it to be, because the cognitive dissonance was so great when “Open didn’t always win”
Sorry, but this is bulls*t.
The iPhone has, what? A few million applications from third parties? It's a platform.
Use the iPhone with 0 (ZERO!) third party applications for 1 year and then get back to me ;-)
Actually, even if you somehow manage to do it, that's not even the point. The AppStore makes something like $60bn per year. iOS is a platform.
The iPhone is not a computer platform, it's an integrated experience. Raspberry Pi or the PC you assemble is a platform (which you can still choose to do, if you want).