You’re imagining a “greatest aspiration” that doesn’t exist. macOS has an iCloud login button in the Settings app and that’s about it.

Sorry, but you're wrong. Music-dot-app is a great example. Check out all the ways it tries to upsell you even if you just want to play local files: https://www.youtube.com/watch?v=anrB6fP1WeQ&t=65s

- opens to a full-page Apple Music subscription service ad on first run.

- search functionality defaults to “Apple Music” instead of “Local Library” (or “iTunes Store”) even when the user has no active subscription.

- Apple Music subscription upsell banner ad along the bottom of the search results screen, that stays on screen as you scroll the results pane.

Check out at the end when he demos Music-dot-app's Settings pane changing to include CD-ripping settings when and only when a CD drive is available, something they could also do and chose not to for Apple Music subscription service when the user isn't subscribed.