They are bad guys, and bad guys should get their comuppance by the end of the story. Besides, they already survived the end of the last age. They don't need to survive the end of this one too. Enough is enough. If any bad guys survive, it should be new bad guys who have made names for themselves in this age, and can then take their place as the "big bad" in the stories and legends of the next age. The Forsaken and their time are done.

And I'd feel the same way even if Be'lal and Asmo, my two faves, were still running around instead of the crew we've got, who all bore the hell out of me