No I'm basically saying that instead of sending out a new random DLC every month with a couple of new missions, clothes/weapons/items , and perks, they should take a bit of time. Take a couple of months to slowly go through all the ending clips (this is a team not one guy it won't take forever) and at least attempt to make a world that changes to what your story ended as.
1 - It may well be a team, but it wouldn't surprise me if that team was small. Happens a lot after release, that the team that continues the work on patches & other stuff shrinks by a lot. IIRC, at one point Diablo2's entire team consisted of...one person. Now, that's different because years had passed, not saying there's only one working on NV. But they do shrink.

They do have other games that they move on to, and a lot of the "team" ends up being dedicated to new projects instead.
2 - to do all that after the game has already been released is probably not "profitable" in terms of hours spent, employee hours paid for, etc...while DLC's (I'm guessing) are. Or at least have a good chance of being so.
3 - if they wished, they could try to put such things into the game from the get-go, but then release would be delayed and often developers are on short time-leashes to begin with.