Gran Turismo 5finally released on the 24th of November, 2010, but people sure waited a long time for it. I won't try and quantify if Gran Turismo 5 made the wait worthwhile, but at least you won't suffer through the same waiting period with Gran Turismo 6.
When speaking with MCV (The Market for Computer and Video Games), product manager Josh Walker said that "There is no reason to think the proposed release window for GT6 will not be achieved."
Walker's claim, although difficult to prove or dispute, must make fans of the series even the slightest bit weary considering the numerous delays of Gran Turismo 5.
The GT6 announcement surprise many as the racing title will only see a PlayStation 3 launch despite arriving around the similarly proposed launch window for the PlayStation 4. But if you plan to purchase a PS4 and need your car fix, DriveClub will launch with the next generation console, which might explain Gran Turismo 6's single console release.
To explain the PS3 release of Gran Turismo 6, Walker went onto say:
"We feel it is important to continue to support our loyal PS3 users, and those from many parts of the world who are new to the PS3, with a new title. And Kazuori Yamauchi (the series producer) was keen to develop the Gran Turismo platform further on PS3."
Walker explained that each Sony console saw 2 Gran Turismo games release in their life cycles. The PS3 will follow the same pattern.
Gran Turismo 6 will launch this holiday on PS3.
Source: MCV
