I'm going to call this bull unless you have some links to back it up.
If the developers say anything at all, it's that programming for the PS3 is different and more difficult than the other platforms. Porting between the 360 and PC is pretty doable, which is why we're seeing a lot of 360 games on the PC as well.
Also, for most of the cross-platform games the PS3 version is inferior, the only exception that I know of is Red Alert 3 and that was released 6 months after the 360 one.