At the risk of being harsh, most of what you posted there is garbage. A franchise that declines from one itereation to the next is typical, regardless of gonig multiplatform. Also spinoffs and handhelds are silly comparissions.
Rachet and Clank: 3.33 million. Every game after that declines until we get offerings like A41 selling 1 million on PS3. OMG! Staying exlcussive killed the sales of the franchise!
Can you show any third party exclusive that stayed PS exclusive that had sales that actually increased this gen? No? OK, discussion closed.
That said, there is a seperate argument to be made that "masscote" exclusives are better off as exclusives. I am speaking of Crash Bandicoot. Crash is a weak character and a weak game but it had decent sales because Sony did great marketing of it in order to battle Mario. It probably would have sold like garbage if it wasn't pitched as the next Sonic. To a lesser extent you could say FF7 got a nice boost being pitched as Sony's "Zelda", so to speak. But these are 1st party titles really. As far as 3rd party titles go, there is absolutely no evidence to say that staying exclusive is good for them, or that exclusive/multiplat has any impact on sales.