I'll start this by saying I doubt this would ever happen. I'll go a step further and say I'm 100% this won't even have a CHANCE of happening within the next 5-7 years (NX releasing probably in 2017 would imply this).
What I'm about to ask is simply for 1) our entertainment and 2) something that COULD happen WAAAY down the line.
What if Nintendo went pc exclusive? What if they made a deal with Steam to 1) include all their games (old and new) and 2) create controllers that work on pcs (you could use any future Nintendo controller still)?
Here is the main question: If Nintendo went pc exclusive, would you even bother buying a dedicated console?
Yes I know, many people buy xbox and playstation and a decent amount of those people may really desire their exclusives, but MOST buy those devices for multiplatforms (let's be honest, the 14 year old teenage boys playing call of duty make up a massive demographic of xbox/playstation purchases). So, if you love multiplatforms and awknowledge the fact that Nintendo's exclusives are either equal to or greater than the combined exclusive list of both sony and microsoft, would you just stay with PC and not buy a dedicated console?
Would it really be worth it buying $400-500 devices simply to play a couple handfuls of games (a year) that are actually exclusive to them? Or would you rather get a good pc (which you could use for a million other fun, creative, and PRODUCTIVE things) in order to play the endless list of multiplatforms as well as ALL of the Nintendo games (past and any new releases)?