I'd personally prefer if we ameliorated your paid tax so that the rate applied over your entire lifetime earnings. That way you could use the same progressive rate but windfall years aren't a special case and lean years are an example of failing to optimise your taxes. You could even have the government refund tax if the windfall event was a once off.

Extra bonus you can get rid of many loophole taxes (like Capital Gains and Inheritance taxes) since these feel unfair to take on a single year basis.

Taxes are what keep the society you were raised in running. You didn't have to pay a comical amount of tolls for roads and bridges, they existed and were maintained. You likely went to free 12 years of education. Some countries do free college. There were police officers to stop the streets from being a war zone. Fire fighters and fire safety laws prevented a single fire in your neighborhood from being the whole neighborhood on fire. You probably don't have a crippling disease from lead toys in your childhood (or at least your children didn't/won't, depending on your age). You probably weren't kidnapped from your home to work in a child slave army or diamond mines.

I get that a government shouldn't have infinite capacity to "milk" someone for free. But why should anyone be given infinite capacity to milk society? When you make 1000x more than you would ever need to live a fulfilling life while multitudes are impoverished, you need to pay taxes so society can build the next successful generation of people. When you stumble upon the ladder to the top, leave the ladder so others can follow, don't pull it up with you.

It would also make them "sticky" and less likely to move away.