Interesting times, for sure.
> and "websites" just turn into data-only endpoints made for AI to consume.
As is already the case with humans, that only serves users to the extent that the websites' veracity is within the intelligence's ability to verify — all the problems we've had with blogspam etc. have been due to the subset of SEO where people abuse* the mechanisms to promote what they happen to be selling at the expense of genuine content.
AI generated content is very good at seeming human, at seeming helpful. A "review website" which is all that, but with fake reviews that promote one brand over the others… a chain of such websites that link to each other to boost PageRank scores… which are then cross-linked with a huge number of social media bots…
Will lead to a lot of people who think they're making an informed choice, but who were lied to about everything from their cornflakes to their president.
* Tautologically, when it's not "abuse", SEO is only helping the search engine find the real content. I've seen places fail to perform any SEO including the legitimate kind.