Luck

It is rather daunting how little people control of their own lives. No one controls who their parents are. No one controls what era they were born in. No one picks how intelligent they are. Disposition to hard work is also just the luck of the draw. Some children are born with crippling disease, despite having done no wrong to anybody.

If pretty much everything about us is determined by luck, it's pretty much impossible to say that anyone really deserves better than anyone else. Even if someone works hard to attain a higher station in life, they may have just been born that way.

A market system can incentivize people to do certain actions. Growing food to feed people. Mining energy to light and heat. While people may deserve their gains from an economic standpoint, it does not directly follow that they deserve it from a moral standpoint. The market is merely a tool to encourage activity needed or desired by people. It is not a tool for determining the moral value of anything.