My guess is that if they now choose to change of director for every other film, it's just because you can't really change the formula, you can merely try to film it your way.
“I think the American people are very smart in understanding our country is very trustworthy with nuclear weapons. We've had them from the beginning. But they have also been critical for keeping the world more at peace than it would have been if it hadn't been for the American nuclear umbrella.”