Instead, the world should move on. But with other paths still being kept open. IIRC Kingmaker even did this early game, but that may be my memories playing tricks on me. You hear about a temporary camp of the Staglord's minions someplace, and are encouraged to travel their quickly. If you don't do that within time, the camp is gone. However, that doesn't mean game over. Thinking about it, stuff like that could be explored by more games imo, as if everything is freezing in place, that doesn't feel like a world. It feels more like a movie setpiece solely existing to wait for you to show up.
Nope, the only variable affecting whether or not the camp is there is...
...you choosing to go after either Tartuccio or the druid first. You could spend most of the time limit exploring and then just going to the objectives and they will still be there as long as you didn't do anything main story-related.
Kingmaker's world is as disappointingly static as it can get with the premise it introduces, that you are building a freaking kingdom. The only area really changing is your capital, and even then the change is mostly visual (although I do like how it looks different for different alignments - too bad the throne room is the same regardless). You'd think that capturing an ancient dwarven forge/stronghold, for example, would have a big impact and provide you with opportunities - whereas it remains the same ruin you found it as for the entire game.
And while most RPGs are much the same in how their locations don't really change as time/story progresses, in Kingmaker's case it's especially noticeable, because it keeps harping on about how you are restoring and taming the land but it stays just as wild as it's previously been.