I agree fully. I think part of the issue is that the folks submitting ads want to collect a lot of data. They probably don't use that data (or if they do, not well), nor do I trust them to not collect very invasive and unsafe data, but I suspect for many folks that having their own JS payload makes or breaks a possible ad network.
Given concerns about Monero mining, redirects, and other hijinks, removing JS from ads is even more critical now. I think the compromise will be to give ads some kind of network provided hook to get data back to "home" eventually, though then the issues above only shift from the ad provider to the ad network provider.