Is that really why people start startups? I'd hypothesize that most interesting startups were started for more fundamental reasons than just to get much wealthier than other people. Many startup founders are passionate enough about what they're doing that they'd do it even their returns were less than what they would otherwise make (e.g. compared to a Google or Facebook salary).

In any case, startups are more constrained by opportunity than desire. Many people have both the ability and desire to bootstrap a startup, but have to work a regular job because they have to provide for their kids, and can't afford the risk. In more equal societies, these people have an easier time quitting their jobs and starting a company.