A lot of the dates are what management put out and try to force the programmers to rush it out the door to get money back. Too many companies are doing what Microsoft started with Windows 98 v1... that is putting out a beta version and getting the public to pay to find them. Then MS went one worse and put out Win98 v2 and made people PAY for it... that was a double offence imho. But most games these days are launched with bugs..
I long for the days when games you bought actually had hardly any bugs... Games like Wipeout on the original Playstation. I don't think I ever found a bug in that... Or maybe Tomb Raider... that was pretty much bug free (and the sequels haven't hardly had any bugs either come to think of it).
I still think the buggiest game to date is still one from the Amiga... Anyone ever hear of a game called Frontier? (a sequel to Elite)... OMFG what a bugfest that was....
