granny: If Diablo 3 sells seven copies and is a monstrous flop, prompting a massive backtrack, I will gladly eat my words and say that I was wrong. But if Diablo 3 sells millions and is quite the success., then welcome to games as a service.
StingingVelvet: Indeed. And it will.
Honestly as I commented on rockpapershotgun yesterday singleplayer gamers are living on borrowed time right now when it comes to mainstream games. Online features and new revenue streams are going to keep chipping away at offline singleplayer until there is not much left, especially on PC. I'm not saying singleplayer is dying really, but traditional singleplayer is.
While it can be argued what "mainstream games" means, I am not just quite as pessimistic. Certainly it can be that some big publishers try to push to online-only mode, but I am quite sure there will "always" be gamers like me who require offline gaming as well. It may mean we won't play Diablo 3 then, but oh well. My life does not depend on it, just like my life does not depend on being able to play each and every XBox360 AAA title (since I don't, and never will, own XBox360).
I think there will always remain a big market for offline games, and if developers like Blizzard refuse to release games for it, then someone else will fill the void. This is the PC after all, anyone can come and develop games for it, something that is not possible on consoles. In the end many of them will make Diablo 3 clones that are better than their example, just like happened with Diablo 2 (or so I've heard, I'm not a true expert with hack'n'slash genre like Titan Quest, Divine Divinity etc.).
A few years ago I wouldn't have believed that there would be sites like GoG or DE where you can buy totally DRM-free games cheaply, even if mostly older stuff. I think GoG and DE prove that there is demand for offline (and DRM free) gaming. After all, a few years ago it seemed like hardly anyone will make single-player games anymore, but everyone tries to enter the more lucrative subscription-based MMORPG business (WoW-style). Luckily, this was not to be.
I think a more probable threat to PC gaming might be that future generations want to play their "computer games" on IPads and Android tablets, where I presume the publishing is just as restricted as on consoles. And I don't consider that so probable either.
But still, maybe fearing about the end of PC gaming is as useless as fearing the end of Amiga gaming in the late 80s. Amiga died eventually, so what? PC/Windows as a platform has obviously proved itself as a more adaptive system than Amiga could ever hope to be, that's why PC/Windows has lived this many years, and still no signs of dying.