They just keep coming down the pike. And a big reason for that is because, obviously, people keep buying them.
If you ask around, it seems like gamers have very different reasons for springing for an HD update, remaster, or remake. And don't forget about those "Game of the Year" bundles that frequent store shelves, typically sporting all the DLC, a few extra goodies, and a lower price tag for a previous hit.
Yes, such products have proven undeniably popular in the new generation. The question is, what makes you buy them? Do you have certain requirements? I mean, if you've already played – and still own – the game in question, there has to be a pretty compelling reason for you to get a re-release of the same title, correct? In my experience, most gamers aren't swayed only by the promise of superior graphics; they need something more to be enticed.
Personally, I'm one of those weird individuals who likes to have the best versions of his favorite games. That's why, even though I don't yet own Tomb Raider: Definitive Edition , I still want it for my library. I have friends who don't care about this, but they do care about playing a favorite game again. And why not do it with the latest and greatest iteration? Perhaps this is why so many are springing for the remasters and HD updates.
And let's not forget the last, and ultimately savvy, group of consumers: They recognize this ongoing trend and, being patient and knowledgeable, they often wait on getting all the biggest new games, certain of a better or more robust package at a later date. Nothing wrong with that, either.