The epic story

Looking at epic destinies in D&D 4e I saw something which jarred with me somewhat: The non-ending.

Most stories don't finish the story of their character once a book has ended or movie finished. Epic destinies are similar in that they end the immediate story and effectively retire the story.

Rarely does a story look at what happens after the ending unless there's a sequel which follows on. Happy ever after is rarely true, so why is it the case for Epic Destinies?

There is a large hole as to what happens once an epic destiny has been achieved but the story doesn't, some epic destinies explicitly don't end but start a new story. We don't have a facility to play out those kinds of adventure yet they must be possible.

So perhaps d&d has space for adventure to continue forever? Not to the extent of 3e and its ever expanding power levels but perhaps through a system similar to how e6 is handled where benefits are accumulated but you never go beyond a certain level. e30 perhaps.