Plenty of stuff you pay for has ads. Newspapers, Cable tv even Netflix are talking about getting them. The corporate imperative to serve the shareholder trumps all others.
Newspapers is free or dirt cheap. You basically pay the paper and distribution costs if anything. Those that do charge to read it online don't show ads to subscribers.
> Cable tv
The main selling point of cable TV was no ads. Eventually they started adding ads, and that's probably the reason cable tv is fading away.
> Netflix
Doesn't have ads right now, and if they do in future, people will just move away.