One needs to think of it as though the PSP is actually making Sony money, PS3 is not. Putting a small amount of resources of the Sony first party is all that is needed to make PSP games. It gives people a reason to purchase the console and sales for PSP games should also increase.
For example GT portable is in development, it has been hinted to the point where it can pretty much be confirmed. Not many from PD would need to work on the game but at the end it would sell PSP's and easily 3 million in software.
PSP and PS2 are keeping the PS3 on life support however soon enough the PS3 will hold it's own. Having the PSP and PS3 both doing well will allow Sony to start pushing back into the black and make significent profit from the Playstation brand again.
The "big boys" are still making the PS3 games so more resources going to PSP by ass, just more outsourcing to 3rd parties to make PSP games.
