as stupid as "generation sales" is Gran turismo is still in the lead:
GT5 7.45m + GT5p 5.35m + GT 3.6m = 16.4 million+
Forza 2 4.0 + Forza 3 5.0 + Forza 3 2.0 = 11.0 million+
thats 5.5 million difference in Gran Turismo's favor, while Forza has 3 mainline entries, and Gran Turismo has just 1 (with 2 side entries).
you have no consistancy, no standards. you always set up arbitrary rules, guidelines and timeframes to try to win arguments, and when one of your previous sets of "standards" fail to win you your argument, you move on to another arbitrarly set of rules. rinse and repeat.
Osamaobama, You win!
Gaming on: PS4 Pro, Switch, SNES Mini, Wii U, PC (i5-7400, GTX 1060)