It's not that straight forward. First because ultra-high earners can and do move abroad to avoid or evade income taxation. So if you kill sales tax/VAT, corpor

It's not that straight forward. First because ultra-high earners can and do move abroad to avoid or evade income taxation. So if you kill sales tax/VAT, corporate tax and other taxes, suddenly it is very attractive for people earning millions per year to move their tax residence to Monaco (or indeed London, for "non-dom" taxpayers), where they don't pay income taxes. Second because there is need for some "fairness" and equivalence between treating employment income and treating small entrepreneurs who do the same. Whether keeping the total percentage of corporate income tax+dividend tax to a similar level as personal income tax, or allowing similar deductions on mortgages for a personal "buy-to-let" rental as for an incorporated rental company, in order to avoid perverse incentives. And while I agree that mortgage interest deductions are an economically counterproductive and regressive policy, that is besides the point if the point is not tax policy but tax dodging...