The factions within the, as you put it, Overton window, share some interests and oppose each other on some other goals. All of the uncertainty in policy lies in wondering whether corporations, politicians or upper level civil servants will get their way in each conflict, sometimes none of them getting their way due to gridlock. Nobody is in control, but some people are in more control than others. As you put it, groups outside the "Overton window" are all dissatisfied - but the really revealing thing is that they make up almost all of the US population.