To be honest, that's the fault of the websites themselves. Google is just an amplifier of a world web wide problem.
I think we can blame google for the login with google prompts given they provide an SDK for that exact use case.
It's symbiotic. Google has been aggregating data from these websites for years to serve as summaries in search, reducing traffic to the sites. More pernicious is AMP, where the site is basically copied to the Google server. This force websites to use AdSense and structure the content in certain ways. If a site doesn't want to use AdSense, or allow Google to summarise the site, it gets down-ranked in search. A death sentence. Further, Google's algorithms routinely promote spam because this is most profitable for Google. Hiding the important information 3/4 of the way down a 10,000 word article with a hundred different kinds of ads on the page. Since the "good" websites have to compete with these spam websites, they either adapt or give up monetisation.
One of the more horrifying stories to read was about [Code Yellow back in 2019.](https://finance.yahoo.com/news/google-2019-code-yellow-blurr...) Google's algorithms were getting too good. Users were finding what they wanted too fast. They'd type in their query, the first result was good, then the user would close the tab. For Google, this meant less ad revenue. They wanted users to stay on Google for longer. *So they chose to degrade the algorithm quality.* Users would have to click multiple links to find the information they wanted, and inside every link was ads served by Google. This is one of the pivotal moments in one of the worst cases of enshitification in software history.
While true, google can punish them by ranking the offending sites lower than non offending ones.