With the Fallout 'Endings' It was less of an actual ending, more of a Storyline Intermission partially see-able thanks to the 'War Never changes' speech that normally only intros a fallout game rather than ends it. I personally think that Bethesdia is going to continue the plotline with one of the expacs they're goign to put out, rather than them all just being Sidestorys like they have before.
I mean, I really hope they do, those cookie cutter endings don't really.... END anything. Sure you took down your rival factions, but now your faction is pretty much out of work and your free to go roam around. And seeing that the Storymode got me to level 25 as a character with 9 int, and there's, what... 55 levels? Yeah just too ripe not to Make at least ONE of their DLC endgame content. Or at the very least will endit the endings if done before the end of the story quests, like how the BoS vs Enclave expac did in Fo3