It's simple, you start at the top, by imposing a 70% tax on the higher brackets as Cortez wants. If the marginalized group would get too wealthy (straw-man argument), the 70% tax would still do it's job.
Who earns $1B as income? I seriously don't think that is a thing. The big earning usually happens when companies or stock gets sold. And yes, it would hurt incentive and takes away funding from capital investment.