No. Had it not Halo at the start, chances are it would've died fast. Now though, after the 360 generation (was it 7?), it has enough exclusives to keep it going. Things like Forza, Gears, Crackdown, Sunset Overdrive (depending on future franchise moves) and Titanfall (again, depending of franchise decisions, and not including PC in the discussion) are all enough to keep it strong. Halo is a big corner stone for them, but it is no longer their sole support leg