The problem with a massive development time like this is that what was absolute 'top of the line' technology when the game was started will be commonplace by the time it is released. So, people will be left wondering why the game took so long.
A few years ago those videos would have had people drooling over their keyboards, nowadays it looks about at a level with other games that spent far less time in development.
It might be a great game, but they will never live down the amount of years it took to make it, it will always carry that stigma with it.
I've been reading about Duke Nukem Forever's development since I started playing Duke Nukem 3D when I was 12, and I agree with that. Something tells me that the boffins at 3D Realms want to make a game that will please every Duke Nukem fan, as they claim it will. They did switch between two to three game engines, and goodness knows how long it takes to craft a game on ONE engine. Given that, it's easy to see why they took so long.
...they spent 13 years, I think...