Third parties had no trouble taking a massive gamble when they switched dicks to Sony's PS1 even though Sony had yet to release a system and prove they would not be the next 3DO.
So... It isn't about what sells. It's about industry politics, money hats, and whiny, talentless fanboy devs being overgrown graphics whores (what's gameplay? said random whore) that also think Nintendo's "kiddy image" is something that was created a gen or two ago. It wasn't and they know it. They weren't born five minutes ago. Mario and Zelda have always been "kiddy." There is nothing about Nintendo today that is any different than the Nintendo of the 80's and 90's, where they had all kinds of games selling. Refrain from the easy waggle comebacks because R.O.B. will say hi and probably beat up your entire families in SSBB.
The games of those days were usually better because of the limits those systems had. The creativity and focus on gameplay, while also not overdoing the cinematic aspects lead to more great "great games", at a higher ratio than what we get today. Today we get a lot of "not bads", "pretty goods", "a couple of greats", and some hyped up bad games polluting videogame history forever as I cry more over being surrounded by so many mediocre/generic "good/great" games, and the legacy this will create. I can't wait for those in the future who will call HD grapics "crappy" or "last gen", while carrying on the notion that graphics mean everything and creativity means "no job" like philosophy.
The Wii may be gimped, but it does force those who dev for it to be more creative, less graphic whorey. I wouldn't mind more creative whores to balance things out at least. There are a few out there now.
Graphics whores will stop being such when they decide to focus on all areas of developing, while not being a snob or history-less prick about going back and opening their minds to what made all those classic games so "overrated and nostalgia ridden" in their eyes.
Learn from the greats, gain a creative soul, and give an FU to those who encourage/enforce the graphic whore law, a.k.a. your corporate pimps.
[/rant and whore word usage over]