In your classic scenario, you navigate the SERP and hit various websites, that's a lot of surface area for ads. In this supposed new situation, you don't browse and scan, you just get the answer. The end. It's a way shorter interaction. I'd imagine you see 1 ad. Instead of dozens now.
Also, if you're never hitting any individual websites anymore, surely they'll become hostile, protect content, put up walls, or push for legislation.
This is not a done deal.