Most of the HD plat-forming base are on their online networks. Limbo, Joe Danger, S'plosionman, P.B. Winterbottom, Blade Kitten, Trine, Braid, Raskulls, Shadow Complex, Super Meat Boy (probably the best of it's genre), Quest for Booty and heaps more are available to download between the two platforms. They may not get the same sales compared to the mega games like the five or so Mario games that makes up the Wii's number, but the plat-forming genre is alive and well online and the releases have been pretty consistent and frequent.
Also, as someone else mentioned earlier, comparing the best selling genre from one platform to another can only end badly when people start coming in with FPS console comparisons, RPG console comparisons, Hack 'n' Slash console comparisons and so on.
Bet with Conegamer and AussieGecko that the PS3 will have more exclusives in 2011 than the Wii or 360... or something.
