Hey, I'm late to the party and no one will read this, but ah well, I'll give it a shot.
To try and look at it from a business standpoint, maybe nintendo isn't necessarily the best company to look at indipendant developers. Their online system, (though i've never tried it, don't hang me,) doesn't look like it would be as easy to sift though a couple thousand indie games, because your holding that darned motion remote rather than a normal remote and staring at a list. And then after you purchase it it takes an entire box in... the thing that holds all your wii... aps. Like weather channel. It may just make that too cluttered so that if you get four hundred of these little things, (exaggerating but you get the idea) then people would have to keep scrolling and keep scrolling. I don't know, I'm shooting in the dark.
And the casual players that use the wii, may simply become confused by the subect or process and wonder why these cheap games look and play horribly. (Because most likely they aren't going to hit the nail on the head first pick.) It may even screw up the wii point system or something, I mean, is anything on the wii normally worth less than five or ten dollars? If someone buys one, would they be basically forced to buy four more? I mean, Xbox has the avatars and themes and stuff like that for the smaller prices.
And to allow for indie developers to develope for their system, they would need to tell people how to get a game to use their motion controls. The games i've seen this is hard enough when its done by a proper company, tech support would be a job no one would want to do, and overall it may be to complicated for one person to do a compitant job.
But yeah, I have a wii and i rarely walk by that section in a gamestop anymore. I don't want to look for 50 games for kids... nothing goes down in price and I've lost faith in their motion controls. All this does saden me though because I've owned almost every nintendo system starting with the original NES.
Granted, maybe i'm just being stupid for not having read the source article, but I don't feel the opening to this thread gave enough of the reason as to 'why' they think it is a failed business model to give these developers a chance.