These are, essentially, the same people who believed 3D Televisions would achieve total dominance by the end of 2013. Clearly, the adoption rate is incredibly low, and the number of 3D enabled homes can be counted without taking off your shoes*.
Take a look at the buzz surrounding The Elder Scrolls V: Skyrim. Read some of the previews for the game. They almost all begin with something along the lines of:
"I have to say, it feels refreshingly freeing to be playing a single player only game without any shred of multiplayer."
The industry is clearly already nearing 'saturation', if I can use that word in this instance, for multiplayer-centric titles.
While 'being connected' is something publishers seem to think the vast majority of players want, it's really not. Starcraft II's Facebook intergration adoption numbers are something less than 5% - you'll need to Google the exact figure - so, even among the hardcore, 'being connected' isn't something the market is pushing for.
Bringing that into the single player component is simply the disguise that Online Only DRM systems will take in order to push themselves onto single player titles.
Fable II's orb system was basically ignored because, frankly, what the hell was the point?
If I want to play a multiplayer title, I'll buy a multiplayer game or play the multiplayer component of whichever game tickles my fancy at the time. Then, I mute all in-game voice chat, disable the chat box, and pretend I'm playing with smarter-than-usual bots.
If I want to play a single player title, I'll buy a single player game. Then, I'll enjoy a game experience centred around me.
Trying to mix the two together gets you Command & Conquer 4, Resident Evil 5 and Call of Juarez: The Cartel. Need I say more?
*Its more, but I like to exaggerate for effect.