The real question is... who cares? None of the franchises are Sony franchises - they just happened to be on Sony consoles. As many others have said, unless you are looking to capitalize on the features of a specific system, there is NO REASON not go multiplatform.
Sony has more than enough 1st party exclusives to differentiate the PS3. So does Nintendo. Microsoft needs to catch up there, but they'll only do that IF they want to. As long as they deem it more profitable to buy exclusivity rather than bolster first party offerings, this is what we will have.