Nintendo's customers are the least likely to go to another platform due to Nintendo's unique position in the market. This is a question of video games vs. computer games. Nintendo is the only company left that can really put out a video game system, every other gaming platform is dominated by computer games these days.

Video games originated in the arcades and are based on reflex based gameplay and local multiplayer. Computer games obviously originated on personal computers and are more focused on sophiscated single player experiences; local multiplayer barely exists or is impractical; it's usually just one player per machine. Now think about all current gaming platforms and which one of these two extremes they are closer to.

Nintendo basically has a monopoly on the former category (since Sega is gone), the only question is if they intend to make use of it or choose the path of selfdestruction by trying to make their console a home for computer games. Nintendo's small dedicated userbase you speak of are the people who buy Nintendo no matter what, but if you look at the pace at which NSMB Wii sold, it's obvious that this dedicated userbase wasn't solely responsible for it. Far from it. There is a large pool of people out there who is willing to spend money on games only Nintendo can make. Nintendo just has to make these games and they will be fine.

Er, that's a rather arrogant and factually wrong point you have, Xbox 360 and PS3 are video games just as much as Wii games are, nothing Nintendo do is more special, they just chose platformers over FPS, they're still video games.

Nintendo's customers are most likely to abandon them, apart from the fanbase (which is small, wii didn't create a fanbase it created a buzz)

I don't remotely buy the NSMB Wii argument, put that on a Nintendo Gamecube esq title and see how it sells.

What is a fanbase if not people who respond to the buzz around games. Can we filter out the people who flutter around the "buzz" of Xbox LIVE, or the buzz of Call of Duty?

buzz is itself a buzzword, and does little to formulate an actual argument.

Er, that's a rather arrogant and factually wrong point you have, Xbox 360 and PS3 are video games just as much as Wii games are, nothing Nintendo do is more special, they just chose platformers over FPS, they're still video games.

Nintendo's customers are most likely to abandon them, apart from the fanbase (which is small, wii didn't create a fanbase it created a buzz)

I don't remotely buy the NSMB Wii argument, put that on a Nintendo Gamecube esq title and see how it sells.

I think his main point stands. 

You can't use NSMB Wii to show how much demand there is for typical Nintendo titles, regardless of the context.

The Wii was a mainstream hit (due to motion controls/price/uniqueness/little direct competition), and so i'd say a lot of NSMB Wii sales were simply from Wii owners who heard that this was the next big Wii game.

In other words, you probably aren't going to get the vast majority of these buyers flocking over to the WiiU just because it offers Nintendo games.

Much like what Rol said in the reply above mine, you've listed every single reason the Wii sold except for the main reason. Games games games games games. The only reason any feature on a console has value is due to the utility it provides for games, and even then, compelling games can emerge that make no use of that utility (NSMBWii being a critical example here). The only reason anyone gives a damn about Xbox LIVE is its use for games, and similarly the only reason anyone should give a damn about how strong x or y console is is because of games. Wii's low price was irrelevant, indeed even detrimental, since Nitnendo left money on the table that they could have taken easily