GT7 will come to PS4 anyway and they'll use the same models from the PS3 games so development time shouldn't be much of an issue and a GT7 should be seen within a couple of years.
GT6 on PS3 allows them to make a tonne of cash and reuse the same engine, and of course prevents the murder of driveclub.
I am a little disappointed, as I really wanted to see what PD could do with next gen hardware using their amazing franchise.