That "just" is an arms race so fantastically difficult that the current leading business doing it has a market cap of $1.4 trillion.
Those algos are, to date, some of the world's most sophisticated uses of AI.
This is like observing that the howitzer was just invented and saying, "Don't worry, we've got chainmail armor."
Also assuming you meant 1.4T=Alphabet, I cannot go along with your pretending that the 1.4 trillion dollar cap is a function of PageRank, nor can I pretend that it's remotely related to whether they can continue providing good results post-chatGPT.
Why don't you think they can handle it?
Between the 0.0001% we care about and the 99% percent that’s automated trash, there’s a solid 1% of content churned out by actual humans at very low quality. Think about things like recipe fluff, “news” articles for noname organizations, and all the super low effort blogs giving Birds Eye view summaries of things like Kubernetes ripped right off some other intro material.
ChatGPT produces straight up better and more informative content than those actual humans, and I am almost sure that it does so much faster and at a lower price. Actually, I think in some ways ChatGPT produces better content than most of the users on Reddit these days too
If they can't do it, we have a problem.
I guess there's the additional problem of bots posting comments everywhere, but that's really just a problem for social media sites and so I'm fairly unsympathetic.
People do spend a lot of their time these days on social media, but that's a new phenomenon, and I doubt it will last, so I don't think the future web is ruined.
Potentially it doesn't really become more difficult.