You’re conflating UI and UX. People don’t care. There are ads on the internet, why aren’t there ads in the os?

99% of people can’t tell what an ad is. Is a trial software an ad? Is a shortcut on the start menu an ad?

People want a bmw, they don’t care that heated seats are now a subscription service. People use YouTube, they see ads as part of the entertainment.

For majority of people, they don’t know there’s better so they don’t care.