Except, jokes on you, you may still owe the US taxes even if you don't live there but you get income from there, and they expect you to fill out your worldwide income and file taxes if you're a US citizen.
> So why would I just sit quietly and let you tax me at 90%, exactly?
Extradition treaties and/or freezing of your bank accounts, businesses and resources within the US.
Nobody expects the Spa.. I mean IRS.
> if you're a US citizen
That's something you can opt out of. In fact, some do: http://fortune.com/2016/08/11/us-citizens-renounce/
Now it's different. I'll be laughing with my other billionaire buddies about your tax rate plans while snorting coke of a hooker's tits on my private yacht and watching the Monaco F1 GP from the harbor. I've got all the luxuries I need over there, and in fact, everywhere, that I previously could only enjoy in the US. I can talk with who I need to talk to over Skype, I can do my business, banking, everything, remotely.
It's not like other countries don't have equal or better infrastructure. It's not like I can get clean water and food only in the US that would somehow make this a magical place I'd never leave.
So why would I just sit quietly and let you tax me at 90%, exactly?