Poor Rol, I think you've done a good job here 
It's an interesting point, but more accurate would likely be that most 3rd parties didn't care in the early days of the Wii, and Dead Space is the classic example. Why release an inferior prequel to a game which isn't avaliable on the console in the first place, whilst other, superior games were being released on the system? That's why it had poor sales
3rd party games on the Wii have good sales (MHTri, Goldeneye, Epic Mickey, UDraw, Just Dance 2, COD last year for example, as well as other games like Resident Evil etc.), some have average sales (Conduit, Red Steel 2, MAdWorld for example), but there have been very few 'bombs', and even fewer which are not in 'niche' genres.
And this isn't an issue solely on the Wii either. How about Nier, Dark Void, Bionic Commando, Alan Wake etc? People just pick on the Wii because its easy and people won't question it, because it's been 'confirmed' with misconceptions like the one in the OP, whilst games which 'bomb' on the HD twins are ignored and when its brought up people say its 'against the norm'
All these games which 'bomb', there are reasons. Sure, some games deserve more sales, and the Wii audience is stupid and buy rubbish games, but simply saying the issue is people who just buy Nintendo games is a bit nieve. There's far more issues than you may expect.
