The game makes it quite clear when you cross the point of no return. (It was clear for me at least.)
So people could easily make a savegame at that point and stroll around the world at their leasure.
Having games like Skyrim continue after the main quest is over, it makes sense. Stuff respawns.
But in D:OS, what else is left to do? Enemies do not respawn. So you can only wander about, doing nothing basically.
