Isn't the game called "Gran Turismo" though? I'd think that without auto racing, "Grand Touring" cars wouldn't exist. If it weren't for a few rich and daring drivers in the 1890s, the concept of automobiles designed for more than just transportation would have been seriously delayed. In fact, motor racing almost died in the 1903 Paris-Madrid race, when the public at large finally realizied that racing was deadly. The French government was outraged by the slaugther in the 1903 race that was known as "The Race to Death". But racecars survived. These performance machines, with the help and courage of those willing to race them, would inspire new categories for the automobile; the sports car, the touring car, the roadster, and other categories associated with speed.
PD has said that GT is about the history of the automobile, and to dismiss the evolution line of vehicles that formed the Grand Tourer would be like reading a book without the first chapter, or listening to a song without an opening sequence. The experience would be incomplete. I quote an old proverb; "How can you know where you are going, if you do not know where you came from?"