I don't think we can predict what will happen. At this point anything seems possible. GT6 can make sense as either a PS3 or PS4 game, or even both for that matter. And there are reasonable arguments against these possibilities. But the business needs to make money.
If Sony and Polyphony Digital can sell 6,7,8 million copies of a game for the PS3, and make it available for PS4 via Gaikai, why wouldn't they?
If GT6 is released this year for PS3 it would make a lot of money for Sony and give Polyphony time to work on the PS4 hardware. They might offer a GT-HD/Prologue sort of demo soon after, while working on GT7 for 2014/15. But we just don't know enough about what's been going on to tell which option is best.
It's possible that part of the team is finishing GT6(PS3) while some of the staff has been working on PS4 development. If the new console is as dev friendly as it was intended to be, we could end up with two Gran Turismo games in relatively short succession. Something like we had with GT2 - GT3 would be a win-win. Time will tell.
Best of luck Polyphony Digital
So GT6, which is not even announced, will be released this summer you think? And GT7 Prologue just a little more than a year from that?
Gotta love how people reason...
I honestly don't think we can reason through this. We simply don't have enough information right now and things change. We can't say that something definitely will happen because of trends. If anything the PS3 generation was the exception and the PS4 will get us back to the rule. maybe
It seemed likely that GT6 would be held for the PlayStation 4, but I expected that console to be announced at E3 which didn't happen. Who knows