Ninty's success isn't solely from motion controls, but rather, that motion control games are going to be casuals invariably, and that Ninty's culture inspire's a cutsey kind of game, which works great with casuals. I wouldn't classify mario or metriod as casuals but then again there are a whole slew of em in the Wii's game library, more than the other two will have for years, and probably the PS4 and 720 as well. lulz
The cheap thing also works well with the casual strategy b/c I could imagine paying more than $300 for a casual-machine so everything in nintendo's strategy from game selection, to motion-control , pricing, and emphasis on first-party games where Ninty has a lot more control in order to require this cutsey-poo style of game.
So, it's not just the motion control thing, but rather that a lot of things that Nintendo has done right are working together.
