Is this related to a decrease in Google’s payment to site owners? Can they choose to enable it or opt-out?
If you told me the small, tasteful, text-only Google Ads of the early 2000s would morph into something that obscures the entire page while still dominating the ad market, I’d call you crazy.
Together with the pricing increase of Google Workspace, (doubling in just one year, in my case), drastic reducing the reCAPTCHA free limit, etc, it seems reasonable to me to assume that Google’s profit are declining to an unsustainable degree. Or is it just confirmation bias?
Unfortunately, there are only little things for users to move this dynamic as we typically have no way to pay for most of those free web sites in the current business model. Publishers are usually taking more money from ads than from subscription or micro transactions, so I'm not surprised if they decided to show more and more full page ads...
If you opt in, Google gives you a knob to control the ad load, and a way to run A/B experiments, but there's nothing reported in the results of these A/B experiments that lets you make sensible tradeoffs about the quality of your website. The system encourages you to turn the knob all the way up.
Consumers can't really go anywhere else. All search solutions are terrible right now. All ad serving solutions are equally terrible. The best solution is to get an ad blocker and if you're trying to serve ads then target your audience yourself.