It won't happen for the big franchises and the reason is simple.
HD console combined still sell more software than the Wii and the sales on those platforms are more predictable than those of the Wii for third parties.
Even if the Wii is close to 50% in hardware marketshare, it still is quite far off in software....
That and you just can't have games that are similar between the HD consoles and the Wii except games using very low resources like Guitar Hero.
So you get one of 2 things :
- HD version ends up looking better and usually Wii version sells poorly ( definitly sells less than 360+PS3)
- HD version ends up looking like the Wii version and sells very badly on the HD consoles...
PS3-Xbox360 gap : 1.5 millions and going up in PS3 favor !
PS3-Wii gap : 20 millions and going down !
