I have YouTube Red so I'm not affected, but I really hate how it's implemented for Google accounts with your own domain. Bringing your own domain and paying Google for the privilege makes you a second-class citizen with Google services. I oppose this because paying Google is not enough, and often makes for a worse customer experience.
Not yet. See Netflix. They will push ads on paying customers and then add a higher tier that is ad free (saying nothing about you, you might just pay more to stay add free, no judgment about you here)
Remember when you paid for cable so there weren't ads (yeah, I'm old)?
The best was a retrospective (20th or 25th) on CNN one NewYears in the early 2000s, which had old footage of CNN. In one of them, the anchors were bragging about how they didn't have ads that biased their coverage of events... Then it broke to an ad. I had to laugh, because the (unpaid?) intern who put that together had to know how it was going to look when actually viewed by the public.