i think it will do 4-5 million lifetime(360,ps3,pc). That is not a flop at all. Thats good-very good even if it has been in development for 7 years. Alan wake was in development for around 5 years and its sold(including digital) probably 1.5 million, and remedy called it a commercial success.
Halo MCC will sell 5+ million copies(including digital)
halo 5 will sell 10 million copies(including digital)
x1 will pass ps4 in USA, and UK.