Tax avoidence is a fixed cost. That's half of why a steeply progressive tax system is tricky. The other half is that people have a keen understanding of the v

Tax avoidence is a fixed cost. That's half of why a steeply progressive tax system is tricky. The other half is that people have a keen understanding of the value of money. Those two things are why the more progressive a tax system is the more variable the revenue it generates. See California which veers between feast and famine.