It has begun a long time ago, where wealth was more then an opinion, it was a loud voice with a lot of information. Rich people are often smart, if they aren't that smart, they have smart people working for them.
Basically, what do you do with wealth and smart people? "Create" information that forms opinions. There are many ways to rule masses of people by injecting and forming different opinions about everything really. Usually it's magazines, promotions, TV and etc.
There's other power: "powerful wealthy structures" which allow certain people to candidate to certain positions and then become "successful", then follow the ideology of the "powerful wealthy structure".
Hope you understand what I'm trying to say, this is my opinion.