Sales would go up significantly, but I don't think it would outsell the Wii necessarily.
I have the PS3 and I was a PS2 customer, and really it's just not the same thing. The games have become different, they're not in the same style or level of accessibility. They've really gone up from the mass consumer with the PS3, there's a much more PC-esque vibe to it.
Having bought the Wii a while after I bought my PS3, I must say the difference is really in the product. Sure, price plays a huge role, but regardless of whether or not you think this is good, the PS3 was not crafted for mass consumption like the PS2 and Wii were. Both in terms of games and the system itself, there are little differences that make all the difference. W
Whenever I play a great PS3 game it always strikes me how less accessible and mass market oriented it is, versus the games on PS2.