They should be able to get it out in 2 years, but I'd say a portable version within 2 years of the PSP2 release should have priority

That makes perfect sense. So we know sony wont be doing that.

I don't know, in previous gen's there has been a 2 year gap, but given the sheer length GT5 has taken I don't think it can go from 5 year gap to 2. So more than likely 2013. At which case we'll be a year into the next gen? I can't see them starting work on a new GT 1 year into next gen .. however if GT5 sells as they expect, they can then put GT6 out this gen, and launch GT7 late into next gen without fear of it not selling or doing damage to potential sales.

Here's the problem, if they release it for the PS3, then the first one on PS4 will take years.  If they say they will make it a release title, we will still probably wait years for it to come out...might as well make it on PS3.

Sony wont make the same mistake twist, Sony PS4 will have so Many Launch titles that towards the end of PS3 (like 2012-2014) there be nothing but 3rd games as all of Sony's 1st party teams will be making Launch titles. 

GT6 would be an Great launch title along with a Naughty Dog game, Sucker punch game, an big online title like MAG2 or Socom from Zipper Interactive, many many games will launch with PS4,

Add FF7 Remake to that list and I think we will see PS domination next gen.

I don't think so and I hope not.

They should just use GT5's engine to make other racing games this gen and do things they wouldn't risk on a GT game, and release DLC over time for GT5 to keep it fresh and a continuous revenue stream. 

LOL

Sure it will...