There's also going to be a lot of people complaining that flat taxes are regressive because the marginal value of money is different depending on how much you h

There's also going to be a lot of people complaining that flat taxes are regressive because the marginal value of money is different depending on how much you have. Taking that to its logical conclusion means taxing or subsidizing everyone to exactly the same buying power. I'd rather see a no-deduction, no-exception flat tax that treats all income the same coupled with a UBI to give people a flexible but modestly uncomfortable safety net. Personally I care less about equality and more about fairness. Getting rid of complexity and giving everyone equal access to the benefits of and the burden to support society while reducing complexity and compliance costs sounds great to me. And it still sounds great if my tax burden doesn't change one iota when implemented. If society feels that it's bad to have a handful of mega rich people, look at modifying the competition laws that let their empires get too big in the first place.