Isn't that alternate reality the current reality?
For whatever reason, developers and some users expect an app to look the same across all platforms, while also looking distinct from other apps—otherwise, the app looks indistinguishable from a low effort one. This involves creating a design system and departing from each operating system's native widgets.
I'm not sure you're actually describing user's expectations, I think you're describing an oft-held belief about user's expectations among people who fancy themselves UX designers.