http://www.gran-turismo.com/us/products/gtsport/ All the up to date information about what's in GT Sport is right here for you to peruse.
The video which I bet is familiar to a lot of folks tells you their(PD) aim and goal for GT Sport.
Had to put this in there since some folks still seem to think the OP has a point, according to what is listed on the site the OP is incorrect in his assumption.
I fully expect arguments from this as well, but at least I have found proof that the OP is incorrect and the site backs me up, can anyone provide ample rebuttal? OP never once provided any proof of his claim to begin with but we have lot of pages of dialogue. I did mention in my other post that no one has seen much beyond the first tier of mission challenge, yet there are still people actively saying there's no single player. If you have no proof why are you even saying that, I mean a racing with no racing is sort of strange. PD are strange but that would be a new level of strange for them to not have races at all in campaign mode. Can we agree that a majority of us are jumping the gun and, without actual knowledge to backup our position or supplant the information given, cannot say there is no single player. The facts we know are written on GT page, until otherwise it is 100% accurate until the game is released missing what said page stated or the page is update with information to change what was previously fact.
all links are relevant to the post and are necessary to provide back up to my stance on the subject.