First of all, it was apparent through many articles and even the press release that Vivendi first let slip that it was going to be out on September 30th. That put Valve in the "unique" position of trying to reach that date. Obviously, they thought they could do it, but according to my friend there it just wasn't going to happen. I kept quiet about it until right before the Sept. 30th date, when I politely informed people that it wasn't coming out then and would be lucky to reach the Nov 16th date they had set for a while. It doesn't surprise me one bit that people snap at me when I say this stuff though. No one wants to believe negative news even if it is true. Did Valve have something that resembled a beta at that time? I assume yes although I never asked my friend about it. Otherwise, why stick with the September 30th date at all. The fact remains though that they grossly underestimated the amount of work (level design, art assets, programming, and most importantly testing) they still had to do though. Its happened to other companies before and it will continue to happen. Making games on an open-ended system like the PC allows for great gameplay advances, but also requires extensive testing on a zillion different configurations, not to mention net play, and security measures. I think the general game playing public has an inaccurate vision of what making a game today is really like.
Of course, that doesn't excuse either Vivendi nor Valve for making a release date which they couldn't reach. I'm sure they thought they could, but Gabe probably realizes that they'll, from now on, stick with the "when its done" standard that is so prevalent with veteran developers. Just my two cents.
Oh, and SidVicious I'm not lying and my friend does work at Valve. I know I don't have anything to prove that, nor do I want to get him in trouble. You have to take my word for it, and obviously you don't. If you want proof that I knew it would be delayed originally though, check my comment I posted about the subject a couple months ago.