Apple wouldn't have placed the ad if they didn't do the analysis to determine (most) users wouldn't mind. This isn't some intern adding it as a summer project; these decisions go through large rounds of discussions at any FAANG company.
Wouldn't mind enough, to be clear.
And I think you're giving too much magical credit to FAANGs, they measure things the same way as everyone else. It could very well be that this was a relatively innocuous test to see how much users would mind more in the future.
"We figure we can fill up to 80% of the user's field of view with ads before inducing seizures" was a very apt description of such discussions (Ready Player One the movie)