I don't think the real question here is: would exclusivity have been better? The real question is: what idiot decided to launch against Killzone 3?
The potential sales of the PS3 platform have been proven by countless games. Regardless of the 360's generally higher software sales, the PS3 has shown it can shift a lot of units and make significant profits for all concerned. The user base, and the sales potential it wields, is now too high for any company to ignore if they want to make higher profits. So, the problem here is not the PS3's ability to sell games, or whether 360 is just a better platform for this sort of game, or even the game itself (it reviewed well enough), the problem here is the foolishness behind trying to directly compete against a flagship shooter with a new IP.
Bad move.
Anyone could have predicted poor sales on PS3. They were almost guaranteed, at least initially.
