Power
In this field it's not about power in the conventional sense, but all about how powerfully you can influence others. The most important aspect of your job is to be able to argue both for and against the value of a piece in order to get it for cheap and sell it at a significant profit. You're a middleman: You are always trying to get the best of somebody, but not necessarily in a taking-advantage way.
One form of power found in this job is that whatever price you're able to sell a piece for becomes its value, and every sale sets a precedent for similar pieces. In a certain way, you are not only discovering the value of objects, but deciding it for them...within reason.
Whatever power you do have, the market reigns supreme. Then again, there are three very large auction houses that control a major percentage of the game—they are Sotheby's, Christie's, and Bonhams. In any case, if you put in the time, prove yourself to be a killer antiques dealer, and hob-nob with the right mucky-mucks, who knows how high you could climb. If you succeed in the field, you're likely to eventually have some amount of people working under you. No reason to go on a power trip, though.