I’m on record as being pro-income inequality. The more the better, the faster the better. It’d be nice if someone with a national forum ever got a clue.
To re-state the obvious: the poorest people have nuthin’. Always have, always will. How do you force a vagrant to maintain financial resources? Only by enslaving him.
So the gap between that guy and the Steven Jobs of your society should always be widening. If it’s not, your economy sucks. Almost literally.
World's Only Rational Man 
Thing is, the bottom 1/5th 20 years ago is (mostly) no longer at the bottom; 17% of them, so I hear, is now in the top 1/5th. Today’s bottom 1/5th, are mostly “new” entries into the system. There is mobility within our system, both directions, but mostly up for those that try.