Except that there are publicly available court documents from a case against Google showing that in the 2010s they started intentionally reducing the quality of search results (or at bare minimum refusing to roll out fully built and tested improvements to it) in order to artificially boost impressions and click through of the paid ads on their search results. See "The Man Who Killed Google Search" by Ed Zitron on his Where's your Ed At blog.

So it's a combination. Things started going downhill with the popular search engines far earlier in attempts to boost ads and with the hyperproliferation of sketchy SEO tactics, then the whole house of cards got fucking bulldozed by AI.

But I'd also argue that the human internet is hanging on fine, it's just a massive pain in the ass to find good sources and maintain your own personal list of "go to"s.