They already plaster iOS with ads...just for their own services and it's disguised as a system feature.

It's especially obvious if you don't subscribe to paid iCloud and see ads for "Apple Arcade", "Increase iCloud Drive storage space", "Sign up for Apple Music", "Have you heard of Apple Fitness+" or "New show on Apple TV+"-push notifications everywhere. Something that in theory they discourage to use these for promotional messages, but that hasn't been the case for a long time.

Syncing that new pair of AirPods you just bought? Yup - Apple Music free trial ad.