Ads are only 2-3% of Apple's revenue, while Google is ~75%.
Hardware is now purely a way to get you on to the app store - which is why iOS is so locked down and iPad has a MacBook level processor with toy OS.
If you stop looking at the marketing speak and look at it from a stock owner perspective all the user hostile moves Apple is double speaking into security and UX actually make a lot more sense.
This isn’t some hypothetical or abstract scenario, it’s a real life multi billion dollar a year industry that Apple allows on their devices.
You can argue that this is not the same thing as the native ad platform that they run and I’d agree but it’s also a distinction without a meaningful difference.