Robin Hood: [to Marian] It's so beautiful, this place... the woods just now... full of noises... everything so alive. I kept thinking of all the death I've seen. I've hardly lost a battle, and I don't know what I've won. 'The day is ours, Robin,' you used to say, and then it was tomorrow. But where did the day go?
If you've seen Robin and Marion, you know Robin Hood's line, "I'd never have a day like this again, would I? Well, it's better this way." and you know what an epic endgame is all about. It is not about beginning a character's career, or growing the character, it is about endings. It is a chance to do something with a character that will forever change the campaign world, and make that character remembered for years to come. It is about letting a beloved character go, knowing that the character has achieved a peak, and would never have a day like that again.
It does not mean that the character disappears from the campaign world, or that the character need die, or even that the character need never pick up sword and lance and enter the fray again. It means that the focus of play is shifting to younger characters, characters eager still to make their mark upon the world.
Ultimately, role-playing games are about accomplishing something in a world where daily life holds little chance of real accomplishment. Possible endgames are telegraphed throughout a campaign because, if the impossible is possible for you, when you first meet it, then overcoming it means nothing.
An epic endgame is epic within the scope of the campaign milieu. If travel to alternate worlds is common, then travelling to an alternate world is not epic enough to count. Not only are the stakes high in the epic endgame - even if only because death is around every corner - but the challenge is real. This might mean Gary Gygax's Tomb of Horrors. It might mean Harley Stroh's Colossus Arise!. It might mean wresting an island from the Venetians and then holding it from the Turks. Achievement is measured in relation to the milieu in which it occurs.
Every James Bond villain that ever was? All of them have been thwarted while in the process of attempting to achieve their own epic endgames.
Think of the real world for a second. If you are daring, you know where the epic endgames lie. Fort Knox. Mount Everest. The Tour de France. Running for high political office. The Pulitzer Prize. The Nobel Prize. Trying to find a cure for AIDs. You know what all of these have in common? You have to take big risks to achieve anything, and the odds are good that you won't succeed. Those who do succeed in their epic endgames - well, we know who they are. Mother Theresa. Muhammad Ali. Alexander the Great. George Washington. Abraham Lincoln.
They achieve their endgame, or fail in the attempt, and then never have a day like this again. Their star shines bright to beckon others onward, but they have had their day, and the focus of history shifts to those who are daring enough to try to rise from the shadows.
Not every character will achieve an epic endgame. But in a well-managed campaign milieu, lures to achieve something beyond the reach of normal men - or even normal adventurers! - are always in the background. Because that is what life is, and that is what best allows the players to have an opportunity for achievement in the game.
The alternative is "I've hardly lost a battle, and I don't know what I've won." If that's your thing, go for it. It's not mine.