Life has always taken place in a tumult without apparent cohesion, but it only finds its grandeur and its reality in ecstasy and in ecstatic love.
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.
If you look at it ecologically, deforestation is high on the list of things which bring devastation. You cut down trees to build homes, for fuel, and you end up with no trees left, and you have to move on. If you take the earth as a whole, eventually there's nowhere to move on to.