It’s fairly silly that this course of action is the consequence of a desire to manipulate search engine results, but at least they’re archiving the articles before taking them down.
To address the headline, though, I don’t think that anybody reputable ever seriously claimed that the internet was forever in a literal sense - we’ve been dealing with ephemerality and issues like link rot from the beginning.
It was only ever commonplace to say the internet was forever in the sense that fully retracting anything once posted could range from difficult to impossible after it’d been shared a few times.
Only in the modern era dominated by corporations offering a platform in perpetuity have we been afforded even the illusion of dependable permanence, and honestly I’m much more comfortable with the notion of less widely distributed content being able to entropy out of existence than a permanent record for everything ever made public.