People made "will GT5 outsell Reach" in 2010.
Halo Reach smokes GT5. Then you get all the "Halo Reach and GT5 arent even the same genre", neglecting that the comparison was flagship vs flagship. Also the ever popular "Reach released in September and GT5 in November, its not fair!" Ah fun times.
GT releases too far apart now to compete with Halo franchise sales. But even as a 1 on 1 comparison, Halo 4 is a true sequel where as Reach was a main title albiet with different characters. Bottom line, if GT5 cant beat Reach, then GT6 can't beat Halo 4.
EDIT: Also since GT5 got mixed reviews and Forza has been 90+ metacritic and releases 3x as fast, that has begun to shatter the notion that GT is the ultimate game in the genre.
Xbox: Best hardware, Game Pass best value, best BC, more 1st party genres and multiplayer titles.
