Well, I would say it depends on 'what average joe' has.
Which actually goes full circle to the wiimote.
Take.. Oh.. Madden, for example. That has been 'altered' in order to make use of the wiimote. Now, if that is the cool thing.. then other kids will want to buy a wii, their parents will see it as (more) affordable, and that's what will gain popularity.
But if little Timmy has the Madden and uses the wii, and little Johnny has Madden on a 360 and Tommy, Larry, and Billy all enjoy playing Madden on at little Johnny's house, they're going to be bugging their parents to buy them a 360... not a wii.
Oh, and little Timmy will probably eventually do the same because his Madden Wiimote Skills won't be any of use to him when he's competing against Tommy, Larry and Billy at Johnny's house.