I think the main thing is many 3rd parties are just afraid to compete with Nintendo's games. But tough crap! You have to take those risks. If a company is making better games that sell better, as a business, you have to take a step back and examine WHY this is happening, and make an effort to improve it. As of now, I really don't see that effort.
The good news is 3rd party games are finally looking better starting next year with Red Steel 2, Epic Mickey, Tales of Graces, Monster Hunter 3, The Grinder, No More Heroes 2, Fragile, DQX, etc. But there is still much improvement to be made. There is no reason, in my mind, why Wii should not receive the type of third party support PS2 had.
If all else fails, I think Nintendo needs to pull a MS and either work very closely with some 2nd/ 3rd parties, or try to buy some.
