This reminds me of the Final Fantasy IX strategy guide. It integrated with Square Enix's Play Online service but now that FFIX was removed from Play Online, none of the links work any more and the guide is pretty much useless. I'm sure we'll start to see more of this in the coming years. It's not really sustainable to keep a website running forever.
If the service is still running then the added cost of hosting legacy content is near zero. Assuming the site wasn't full of bandwidth hogging live video or anything like that the cost of storage and hosting are almost zero.
Keeping a whole server running however does get a bit more expensive, but you could also rehost it on a cloud provider for a very modest cost per month.
