I got back into a video game the other day that was released 15 years ago (also when I first played it). There were plenty of dedicated websites around the game, most of them with forums that contained guides, little details and secrets and whatnot (matter of fact, I ran one of them for a while).
All of those are long gone, with all associated content - which I suppose is not surprising, given its age. However, the issue remains - as interest in a topic dwindles, fewer and fewer people see the point in spending the money and effort to maintain these sites containing (mostly) unbiased information and the information, alongside potentially thousands of user-generated posts/content in the forum, gets lost in the void. If you happen to look something up you saw a decade ago, you might find it on the wayback machine, but certainly not via a search engine.