I really love Bethseda. They announced a release date for Skyrim way back in 2010 at the VGA awards. Very few games of that magnitude do that these days. Look at SWTOR, still no release date, Diablo 3, no release date, GW2, no release date. Do you think Bethseda is just better at forecasting when they believe a game will be ready, or do other game developers lack the balls to just set a release date, and deal with the potential competition of other games being released around the same time?
Probably a little of both, though I'd bet on Bethesda simply having a more experienced (read: BETTER) project management team than other development houses.
That being said, just because Beth says it, doesn't mean its going to happen. Oblivion didn't meet its original scheduled go live. Personally, I prefer Bethesda's approach. I'd rather hear a target release date and have the deadline missed, then not hear a release date at all. But then again, I'm not one of those people who has an apoplectic breakdown if the release is moved by a few months.