You can implement a progressive tax using UBI and a flat tax instead and thus get rid of all the loopholes and tax screwery. IMO this is what all countries should do. Corruption loves complexity.
I dream of the day that a land value tax, and only a land value tax, covers all government services. In fact, one could argue that the size of government that a land value tax supports is the maximum size.
All excellent ideas. Unfortunately I think a Federal LVT would require a Constitutional amendment, but nothing stopping us from doing this at the State level.
An MMT theorist would argue that taxation is used to withdraw money from circulation and redistribute income. They advocate for using fiscal policy to drive monetary policy.
I just want to state for clarity's sake that I don't espouse the policies of MMT theorists. It's just a framework that appears to have some analytical merit. For example, despite the roaring deficits, why has demand for treasuries not decreased? Why did QE and high government spending not cause inflation? Why do surpluses tend to trigger recessions?