GT has a 15 year establish fan base, it's launching with 25 million more ps3 in home than when GT5 launched.
By week 10 it will be at 6 million. Drive club, Froza, ps4 and XBO are irrelevant when it comes to GT because its a $60 game. Racing fans will buy it due to its proven track record of being the best racing sim available anywhere.
By year 3 it should be at 10 million if not sooner. Never doubth GT!