Do ideas rule the world? No, not quite. Ideas that are implemented might be a more accurate statement. And even if an idea or concept is formulated into a plan of action and put into action, it needs to be of large enough impact and power to be considered as an idea 'which rules.'
How long does it rule for? Well, some ideas are superseded before they even 'get off the drawing board,' and this seems to be the case today with the rapid extention of Information Technology. Other ideas stick around or are superseded after hundreds of years, e.g. Newton's theory is ecplisped by Quantum Mechanics.
A big quesiton is where to ideas come from? The person in whose mind the idea surfaces is not in reality the creator of the idea; at least that's the way I see it. It is the mind trained along certain lines that the idea 'preciptates' into from what some are now calling the Collective Unconsicous. It's a bit like so-called luck: motive, preparation and opportunity, engendering the idea.
Do ideas rule the mind? To reiterate. Not until they become established in the thought-patterns of an awful lot of people.