Wow, you know this? For a fact?! Are you a time traveler?! FOLKS, THIS MAN CAN SEE INTO THE FUTURE AND HE KNOWS ALL!
All sarcasm aside, there will always be hardcore games. Always. There are hardcore games now and there will be hardcore games in the future. To say that hardcore gaming is dead forever is, well ... just wrong. Ever heard of ARMA 2? Trust me, it's hardcore, if only proven by it's overly complicated control scheme.
And speaking of which, what exactly defines "hardcore"? Is it difficulty? Because it seems that obtuse games with fiddly controls, unfairly punishing difficulty and a shit save system is what seems makes a game "hardcore". Also, lack of accessibility to a wide audience seems to also define a game as "hardcore".
If you ask me, I would call "First Person Tetris" hardcore. It's the same old Tetris game from the NES, but when you rotate a piece, the whole screen rotates, making maneuvering a piece into a slot a huge challenge. It can be accessed by anyone, and yet only a few will be able to get to be even marginally good at it. Anyone who can master that sadistic game is one hardcore dude. And yet, it's only browser-based Tetris, but the whole screen rotates.
That's my thoughts on hardcore, anyway ...