That's not true in practice. You always need to file taxes to the US no matter where you live, but you only pay to the US if you paid less overseas (you pay the difference, you don't double pay).
Almost any county you'd want to live in (except tax havens) will have higher taxes than the US.
The rule you are talking about applied only to expatriation between 2004-2008 and then only if you spent more than 30 days per year in the US after relinquishing citizenship.
Authority is the ability to execute on that authority and the USA has plenty of execution ability.
In practice, it's how extradition works for non-citizens who never set foot inside the USA, or bank account freezes for people who don't live in the USA.
Only if they decide you did so for tax reasons (which is just a formula they apply to your earnings and assets. hint: if you're going this route, do it fast as these numbers drop every year).
