It never "made sense" to me, no, but if you were a server making more than the chef or GM, wouldn't you be loathe to give up your income? haha
There are cases in the business world where salesmen make more money than their managers, though. Perhaps it is more analagous to that?
In a certain sense, since the majority of income for servers is based on risk, as commission-based pay always is compared with salaried pay, it may be somewhat justified? Economically speaking, the higher the risk, the higher the reward and whatnot.
But it is absurd that servers probably make more than owners in many cases.