Gran Turismo 6 on the PS3 will make Sony a LOT more profit than if they put it on the PS4. That's the point of doing business. GT is a franchise that does very well in Europe, where the new console adoption rate is lower.
It's also playing on the repeat customer effect, where you stand a greater chance of a consumer coming back if you make them happy.
It's clear that Sony's strategy is to sell two levels of consoles, just like a lot of other businesses with a lot of other products. It's not to make fanboys happy by allowing them to say, "my next gen console is out-selling your next gen console". It's the Corvette and the Camaro, the Big Mac and the regular cheeseburger--though, wait, that might not work since I always get the two cheeseburger value meal.
I think it's going to be fine. Those who want a PS4 are going to get one.
