It is pretty simple, the Wii sucks technologically. It has no chance of playing any game made for the PS3/PC/360 and so they would have to develop it again, from scratch, with lower resolution textures, less zombies on the screen and less ambitious levels.
If Resident Evil 5 was a PS2 game the Wii would have it right now. I mean look at Dead Rising, it doesn't even look fun with all the changes (and it was one of the few 360 bright spots when it came out early in the gen). The Wii simply cannot handle modern games and so they are not ported.
The Wii may very well get an on Rails version 2 years from now that will be worse in every way, but Nintendo really took the console out of the running for any kind of cool cutting edge games when they made sure their console was a full tier below the competition and thus pushed out of the development cycle for HD games.
Also its not like Capcom needed the Wii in this case, RE5 sold millions across the 2 consoles no problem (even a bunch in Japan). If the Wii wants these games all it has to do is make an HD version.
In a related story why can't I buy a 386 with Windows 95 and play Crysis? You can say good things about the Wii if you're so inclined, but "it handles modern games and can fit in with the production cycle of the 360 and PS3 where 3rd party games actually get sales" is not one of them.
PSN ID: ChosenOne feel free to add me
