@Darthdevidem01
Do you realize that half PS3 owners will have to buy GT5 to reach your 10 millions? Even if the userbase reach 30 millions (late 2010 or early 2011) 1/3 of PS3 owners will have to buy this game to reach your expectations. So to answer your question this is why GT5 won't outsell GT4.
@Tbone
Yes and I don't think GT5:P will reach 3 millions by the end of the year.
@skeezer
If you have something good to say about GT5 sales go on! Otherwise...