In hundreds of years from now the human race would have ridiculously powerful technology. We already have lasers,drones and complex firearms. In hundreds of years we would have heavily armed machines(robots) and extremely powerful weaponry that we can't even imagine of right now. If we were attacked by aliens or such we could simply send machines/drones to easily annihilate them. In the movies however the setting is always us turning tail and running away like primitives and getting overwhelmed.