Except that they can.
Nintendo has won tons of money with the Wii. And that industry is moved by the money. If they really wanted to move the hardcores to the Wii, they will do it.
Going to NIS and saying: "Ok, I want Disgaea 4 for Wii. Completly creative freedom. I know that It won't sell much, but I will support any loss if your game is over 80 in MetaCritics. Each point over that value will be 100k $"
Then, going to all the small japanese companies that made good enought Wii games, but that can't afford to translate and distribute their games to US, and saying: "Ok, I'll pay the translation and I'll distribute the game to US and probably Europe, keeping a low percentage of the benefits. Win-Win for that companies, 0 cost and the possibility of get fame out of Japan".
Then, going to all the indy scene and giving really good conditions for development in WiiWare. No more "I'll keep all the money of the first X sells", that discourage a lot of people, that fear that if the game don't sell much, they win 0$ for all the effort.
Taking risks as distributing or even producing M games, like Madworld. Getting small teams that works well with the Wii hardware but don't have enought game design experience, like the people of Conduit.
Talking with all the big third parties, like EA, Activision and Ubi, and saying: Ok, I'll discount the 75% of the royalties that you pay for develop for Wii (that is like the 20 or 30% of the final price of the game) if your game get's more than 80 in Metacritics. And if the first reviews are over 85, I'll promote your game with X$ in TV and magazine ads.
And also, the other obvious things, more freedom and suppor for the online, better and cheaper devkits, etc.
If Nintendo really wants to move the hardore to the Wii, they have enought money to do it, and even without sacrificing a great part of their benefits. It will be slow, but the hardcore will have to surrender to the evidence of the catalog.
I hope that Reggie is not reading this post, I'll hate if Sony and MS gets bankrupted by my fault.