But you see, that is part of the problem from the other direction. Everyone - and I mean EVERYONE - operates on risk/reward considerations, whether consciously or instinctively. It's an evolutionary thing. From the J.P. Morgan or J.D. Rockefeller investing in some factory, bank, or other business - to the toddler standing at the edge of the waves on the shore looking at the water longingly yet fearfully - we all consider risk before going forward.
So... you want to tax the rich. OK, I get that. When famous bank-robber Willie Sutton was asked "Why did you rob so many banks?", his answer was "That's where they keep the money." So you want to tax the rich because they are the ones who have the money.
Hey, it's logical. EXCEPT that every person understands that there are risks in all major (and quite a few minor) choices. INCLUDING the risk that they lose more money through exorbitant taxes if they stay than taxes in other nations if they leave. Risk/reward at the personal level. Everyone has their own level of acceptable risk. When the tax liability risk becomes too great... Bye, Bye, Miss American Pie. If you want to keep all that money here, you have to let people keep enough of it to not trigger the risk that leads to flight. Go ahead, try to legislate that so that they can't leave. OOPSIE, there is this little constitutional freedom of movement clause that could tie up such legislation forever.
You cannot forget McCulloch vs. Maryland (1819 SCOTUS case) when then-Chief Justice John Marshall offered the statement "The power to tax is the power to destroy." He was talking about states taxing a federal bank, but the statement is valid for more than that narrow case. When you tax the bejeezus out of the rich, you are looking to destroy them. Well, excuse me, but

that. You have long ago described this as a class struggle issue. Well, sometimes the classes exist as they do because they are too lazy to advance themselves. Or they are too dumb and they know it. Or they are too afraid to take a chance on bettering themselves for fear of failure. Or they fear persecution for daring to attempt betterment. I don't claim to know why classes form - but they do.
Even when Russia was strictly communist, oligarchs came into being. Even in socialist countries, there are haves and have nots. Over 2000 years ago, Jesus offered the opinion that the poor would always be with us. Attempting to destroy classes - by riots and rebellion, government oppression, excessive taxation, or any other method you want to name? Doomed to failure as demonstrated by pretty much all of recorded history. Go ahead and spit into the wind. Hope your shirt is washable.