Whichever developers (3rd party) haven't showered the Wii with support at this point probably won't in the future either. Its been well over two years and throughout these two years everyone's been saying how developers will wake up and start shifting massive resources to the Wii. (There are threads and news speaking of major shifts, but it remains talk most of the time and by and large there isn't much difference between now and, say, a year ago).
This gen is very different in that it shows that having the largest install base doesn't automatically equal selling the most games (unless published by Ninty itself, in which case it'll likely set some world record or other).
Developers will remain quite divided throughout the entire gen I think, I don't think anyone is going to suddenly start shifting all their attention to other platform (s) mid gen (not saying we're mid gen but people have had plenty of time to see how well Nintendo are doing both with the DS and the Wii).