I think it's an arrogant presumption to say "devs need Nintendo". More like Nintendo needs devs, not the other way around.
Lets look at where the new developers who have actually made a name for themselves the last few years are coming from:
Media Molecule - LittleBigPlanet series, made their name on the PS3 thanks to investment from Sony
Rovio - Angry Birds has become a global phenomenon and turned this unknown studio into a global powerhouse. Thanks largely to iOS.
CD Projekt RED - Has brought attention to the fact that big time game development is no longer just a monopoly for devs in North America/Western Europe/Japan. This small developer from Eastern Europe made Witcher/Witcher 2 a hit thanks to Steam/PC market.
PopCap Games - Developer of Plants Vs. Zombies and Bejeweled has made a fortune through iOS/Facebook.
Mojang - Developer of Minecraft the massively successful breakout hit that was basically developed by 1 guy in his garage. This game has sold *nine million copies* and counting, including 3 million on XBLA in just 5 months or so.
Team Meat - Indie flash called Super Meat Boy. Became a surprise hit. Sony/MS encouraged them to make a version for XBLA/PSN and it became an even bigger hit. They declined to make this game for Wiiware because of Nintendo's restrictive policies. Ironic since the game is inspired by Nintendo's own Super Mario Bros.
These are just off the top of my head as the big break out devs of the last few years. None of them needed a Nintendo platform. Where are the ones who broke out on Nintendo platforms? I recall High Voltage Software wanting to do a lot with the Wii and had plans for like 4-5 different games, but these were mostly canned after Conduit 2. The Little King Story developers and Marvelous also had big plans for Wii, but they largely have backed off the platform the last few years.
Steam and iOS are the true booms for indie gaming. The three console manufactures are honestly dinosaurs with their $10 licensing fee/copy model. Microsoft is the most progressive with XNA being affordable enough that the average garage developer could make a game. PS3/Wii dev kits are expensive.
