What would happen if Gran turismo 5 and Halo 3 launched on the same day?

[Toefactor]

bouzane said:
@Hyruken
 GT5 YTD sales will surpass those of Halo 3, mark my words.

 

By the time GT5 is released how many PS3's will be in circulation? A lot more than the 18m 360's that Halo 3 had to work with, and I bet GT5 still doesn't beat Halo 3's release day numbers or even first week numbers.