Its pretty simple. the $400 PS3 lacks a shitload so no one wants that piece of crap. 80GB is where its at, problem is its $600. So you have cheap Wii, you basically get what you pay for, or Cheaper than PS3 but still better than PS3.
You dont pick from 360 or Wii, instead you buy both for a $350 Xbox that is currently coming with 2 games (Forza+Ultimate Alliance) and Wii that is $250. $350+$250 = $600.
1 Console vs 2 Consoles
Playstation 3 $600 vs $600 Wii60
The Winner is!?! Wii + Xbox 360 Aka Wii60!!