The SNES won because it had all of the Japanese support... Although it was a fairly even graphical race, and the SNES actually did lose 1 region.. Europe.. That is what is making the Wii so amazing it is winning where even the SNES did not.
End of 2009 Predictions (Set, January 1st 2009)
Wii- 72 million 3rd Year Peak, better slate of releases
360- 37 million Should trend down slightly after 3rd year peak
PS3- 29 million Sales should pick up next year, 3rd year peak and price cut