Third Party Devs have made up their minds about the Wii.

[Demotruk]

Soma said:
Nintendo DO need third parties, they can just make a certain amount of games a year and need all diversity as possible. In fact, part of Wii success is thanks to third party games.

With that said, if Big third party companies do not want to invest on it (with good games and good advertisement), then it's a huge opportunity for small studios to capitalize. Suda 51 may have a huge opportunity with No More Heroes 2, High Voltage with the Grinder and so on.

Back in the NES era there was a big changeover with older, bigger games companies dying because the smaller ones were quicker to take advantage of the NES success. There's an Atari (I think) ad on Youtube from the era with a bunch of third party developers saying how great the console was, the names are completely unrecognisable now. So there is precedent. Unfortunately it's probably harder these days because the barriers to even Wii development are much much higher than the barriers to NES development.