Honestly, they should probably leave income alone and just double down on the wealth tax.
Wage-based taxation has always been an awkward way to target the rich.
I have very different feelings about someone from a poor background who went into massive debt to develop their skills and become a top earner vs. someone who inherited a fortune and doesn’t put any effort beyond checking their bank balance periodically.
Plus, there is the “won’t they just leave?” argument. Which is mostly FUD, but in the case where someone’s wealth is based on their skilled labor they do have a much easier time just leaving. If your wealth is from owning a portfolio of apartment buildings, good luck taking those with you.