For the PS3 and 360 to be freaks that sell well past the normal 5-year lifespan, I suppose you would have to say that their current sales figures (between 100 and 200k a month) are "good".
Would that then make the Wii's sales "great"? Would that then make the Wii a superfreak (RICKJAMES.JPEG)?
I think any software sales decline comes from the fact that you can't simply get by selling Carnival Games anymore, because the Wii already includes the premier collections of that sort of software with Wii Sports and Wii Sports Resort. Nintendo games never seem to suffer sales decline - but that's because they are both good, and in many different genres as well. Third parties can't seem to put their whole heart into making top games in all genres and selling those instead of Spinoff Franchise Party 4, B-Team Railshooter Port Remix 8, or C-Tier Franchise Late Port.
Yes, people are buying less third-party games on Wii, and honestly I understand that because I don't want to buy Rygar ports from 2002 and I don't want to feel like a forgotten gamer when Capcom will put Street Fighter IV on an iPhone and not on my Wii. I like the ultrahardcore/quasi-obscure efforts that some third parties make, like No More Heroes and TatsuCap and such, and I buy them when they come out...but third-parties are fools to think those are going to move units in lieu of the other, bigger new and old franchises.
Ehh, this is the same song and dance in every sales-related thread dealing with Wii though.