A much-needed advantage is also keeping old devices useful. Every Apple phone slowly outlives its supported software to the point where the official AppStore has almost nothing in it. Today, it's extremely difficult to find 3P apps that work with my current iPhone 7, which is not that old, because the ecosystem cuts off old phones very quickly.

I agree, and, if you have a developer certificate from Apple, the list of wants I have is ... not that long? zero? I'd love to be pitched on it. In practice, I wanted freedom, but didn't really want to do anything with it.