There is also a large group of people who either bought a Wii and later stopped playing it and bought a 360 because of the graphics and not really enjoying motion controls, or waited and never bought a Wii for those same reasons... a lot of people also left Nintendo this generation because of the controller or even less 3rd party support then they were use to.
There are simply a lot of people in this crowd, most of them never bought in to the Nintendo is kiddy until the Wii and a lot of them are willing to come back as long as Nintendo shows that the Wii U is more capable then the PS360... I personally think that the demos showed that, and even a lot of nah sayers say that if the next Zelda can look like the demo or better, they will have no problem with the power of the system.
People also change their minds easily, this is why the 360 became the dominate dudebro platform, not because Microsoft did everything right (paying for live from a loyal fan base stand point is actually losing them customers now, of course from a business stand point, it's just the right thing for microsoft to do) the real reason people changed from playstation to xbox was due to games being inferior on ps3 or not there at all in the first 2 years of xbox 360's life.
That is what is important, Wii U has a year head start, and they will take some PS360 users between xmas 2012 and xmas 2013. If Nintendo can offer games like GTAV and COD(they will) there is a large non fan base that will move to Wii U.
If Wii U can connect with the Wii's party influence at all, I think we could also see another Wii Situation, all it would take is Wii Sports 2 and another piece of software the media can run with, plus the most important part is Wii U selling out for the first 6 months, if it can do that... It won't only be the market leader, but it will get every 3rd party under the sun in their corner... however, that unique software that can get the media's attention... that is a tall order even for Nintendo.
TL;DR: There is a chance that Nintendo will walk away without the kiddy imagine and be market leader / go to platform for gamers.