Can you describe your desired outcome? Do you want almost everyone to be relatively “equal” like in the late USSR or current North Korea? If not then I guess “inequality” is not the thing you need to look at.
Basically I feel that a person who puts in a reasonable effort (spends 45 to 55 hours a week working, commuting, learning skills, and/or looking for work) should be able to generally live the American Dream which I would define as something along the lines of owning a house, providing for your needs, raising a family, improving yourself, participating in culture, and generally having the freedom to choose your lifestyle.
When I say choose your lifestyle, I don't mean that everyone can become a rockstar or drive a Ferrari. Rather I mean things like: Do I want to live in the city or the country? Is it important to me to live near people that share my religion or culture? Is living near my parents important? Am I a Southerner, a Yankee, or a Texan? Do I want to live the mainstream American lifestyle or be more of a hippy?