I feel the problem here isn't the developers not making enough games to cater to the 'hardcore' gamer (Which is a phrase I hate)
Has anyone forgotten bad games have always existed? You've only got to watch a couple of episodes of AVGN to realise not every game back in the early to mid 80s was automatically good. Plus, there was a lot more games back then, so more good games came out to disguise the bad games in their libraries.
There's also the problem of money. Back then, especially for the Atari and games of that era, ANYONE could make a game for the Atari for dirt cheap. These days, budgets can be as much, if not higher than films, and catering to the wider demographic is the only option for the game designer as they don't want to make losses (Which would be MASSIVE since the 'hardcore' part of gaming is very small).
There's also the issue of what 'hardcore' gamers see as a good game. To me, it seems like a game has to be either System Shock 2 or Counter Strike. I remember an arguement a while ago about TF2 being too lazy, and if only it was more like CS:S it might have been made better. It's something I hate to see, and it appears as though hardcore gamers only want to see remakes of older good games to come out, while anything that does differently is bad.
These days, it's easier to point out a good or bad game, since there's a large amount of things to criticize. Back in the early era of gaming, you could only really talk about gameplay and graphics, and graphics would simply be how well you can distinguish between the different blobs. Now, you can talk about character model graphics, world graphics, game physics, enemy and friendly AI, active and immersive sound, gameplay (and whatever game, good or bad, it rips off), controls, multiplayer...
The reason (Or at least one of the reasons) for a significant jump in recent years is games are becoming either too ambitious and flopping in the end (Fable, Mass Effect and Spore for a few examples) or because a game is so expensive to make to match expectations about graphics and sound these days that catering to the widest audience possible is the only way to make money.
My final point is that it's the hardcore gamer's fault. They have this closed little circle that's like 4Chan. You have to secretly become part of the group before you make yourself known, otherwise it's difficult to get in. Hardcore gamers shun casual gamers constantly for games which cater to the casual gamer. If hardcore gamers want more games catered to them, maybe they should let more casual gamers into their little elitest world.
Of course, if they did that, it wouldn't be an elitest world they live in any longer, and probably end the only reason hardcore gamers want to be who they are: Someone who can ***** about the majority.