Earlier quoted context omitted.
It won't prevent them to show ads. It will prevent them to show targeted ads. So your point is either invalid or rather "they won't be able to be datamining their potentials users to pay the bills" ?
Advertisers are willing to pay way more for targeted ads. If an app is relying on advertising revenue, the inability to target ads will directly cause the app to generate less revenue.
It's my phone, not the developers, not the advertisers, mine.
If you want a device which is subsidized by and encourages advertising and tracking, you have Android or Amazon's devices.