They should take as much money as they can grab, just like the rest of us. If inequality is a problem, I think it's better to address it through taxation than through wage fixing.
imo, the ideal society is the opposite of what you said: people who do "useful" stuff should get to keep most of the value they create, and there should be mild restributive programs to ease the burdens of people who can't really contribute. definitely not realistic, but this is the ideal I think we should shoot for. the team of researchers who cure cancer should be worth more than guys like zucc.
note: I don't mean to single out zucc; I just think Facebook is a good example of a valuable company that hasn't improved the world.
Thus, the tax payers are subsidizing Zuck's income.