Ideas can inspire, as we have seen with the war we have just ended, and the sudden rise of Socialist thoughts in our Political atmosphere. So who can say that another Rome couldnt rise, and this time prevent a rebellion from taking it down? For we must remember, the reason Rome couldnt defeat its rebels, was due to the amount of time it took to put them down. With the iron horse, armies can quickly put down any revolt, and keep order in the areas that need them. All it takes is one charasmatic leader, and one common belief.
Nothing is impossible, everyone said that the destruction of the Spanish Armada was impossible, but the English did it. So maybe in future years, with the rush of expansion in both land and naval warfare, we may see a new power dominating the seas of the world.