GT6 will make a massive profit on the PS3, now, in 2013. A relatively fast development time re-using many of the assets it took them 5 years to build. That's why it's launching there.
They can get another GT out by holiday season 2016, when the PS4 has an install base of over 30m. Anticipation will be huge by that stage, and they'll again make some serious bank.
The alternative would be to hold off on the big profits now, scrap large portions of their engine after it's only been used once or twice and launch to a lower install base with GT6, with GT7 arriving much later in the gen. It's all about timing. GT will sell consoles whenever it arrives.








