To put things into perspective, here is a list of things that have been accomplished between the announcement of Duke Nukem Forever (April 28th, 1997) and the announcement of its death (May 6th, 2009)
-EVERY Pokemon game has been made and released Stateside
-the Beatles had made their entire discography and broken up
-EVERY Sims game has been made.
-We've seen 5 Final Fantasy games, to say nothing of spin-offs.
-We've seen all Super Smash Bros. games
-3 home consoles from Nintendo
-7 Game Boy Consoles from Nintendo
-2 Playstations and a Playstation Portable
-All Xbox Consoles
-The entire Halo Franchise
-Every superhero film from X-Men to Wolverine (more than it sounds)
-Every iPod and the iPhone has gone from conception to market.
-We have seen 3 complete Presidential terms with 3 separate Presidents over 11 years
-The entire Lord of the Rings trilogy was filmed and released
-The entire prequel trilogy to Star Wars was filmed and released
-Every Silent Hill, Resident Evil, and Fatal Frame game has gone from conception to reality.
-Valve released Half-Life, Half-Life 2, Portal, Left 4 Dead, and Team Fortress 2; not to mention developing the Source Engine.
-Independent coders made Counter-Strike and Team Fortress Classic in essentially their spare time.
-We've seen a sequel to Earthbound develop on consoles 5 years apart, get released, get independently translated by a small devoted group of fans and released in English.
-The entire market lives of the Dreamcast, Neo Geo Pocket Color, Gizmodo, and both N-Gages combined.
This only goes through a few of the many milestones. A more comprehensive list can be found
here