I get that the whole "HL2:E3 is like Duke Forever" thing is said as a joke, but it's not that funny.  The connections are just too small.  Yeah, episode 3 is taking a long time.  Still, 3D Realms took TWELVE YEARS to not release DNF.  TWELVE YEARS!  The first Half-Life isn't even 12 years old yet.  Unless you're suggesting that work began on episode 3 before the first Half-Life even came out, there is just no comparison. 
 
Also, what did 3D Realms release between Duke 3D and DNF's cancellation?  A Duke 3D expansion and Shadow Warrior.  Valve has released HL2, Counterstrike: Source, Day of Defeat: Source, Ep. 1, Ep. 2, Portal, TF2, L4D, and L4D2 since 2004 and are releasing Portal 2 this year.  That's a lot more productive than 3DR.

...when it's done.

I am in no way defending the idea of dicking around for a decade on a game's development cycle, but I thought I would add that 3D Realms also put out Prey in 2005, which was a decent shooter that actually beat Portal to the whole tele-portal thing by a few years, even if you didn't have direct control over them.

"I am in no way defending the idea of dicking around for a decade on a game's development cycle, but I thought I would add that 3D Realms also put out Prey in 2005, which was a decent shooter that actually beat Portal to the whole tele-portal thing by a few years, even if you didn't have direct control over them. "

Who said Episode 3 was becoming Duke Nukem Forever?