Yeah agreed, but you also spend a lot of time (and probably money) in complying with US tax laws. I think the US expats that are dumping their passports are doing so because of the unfair burden of paperwork, and the draconian approach by the US government, not the tax itself.
This can be a major (real cash) problem for people in Australia!
Most pensions (called 'super' by locals) are with private institutions - but under strict Government rules such as 9% compulsory annual contributions and no touching it until (usually) turning 60. [No exception leaving the county!]
Unlike in the usual US scheme, in Australia, annual contributions, and annual income are taxed (pretty lightly) and eventual draw down is tax-free. Furthermore, the Australian tax office allows many deductions (such as essentially tax-free dividends and 50% reductions on Capital Gain) unknown in the US
The IRS has declared such funds not to be 'Pension' schemes under the tax treaty and is taxing them with enthusiasm given its new rules. The recent Tax treaty allows sharing of tax information between the US and Australia; so hide at your own risk. Industry bodies and the Australian Treasury have made representation to the US - gone nowhere.
[Ironically, Australian Government Pensions (federal, state, and local) are not impacted.]
The killer is for US citizens who have lived in Australia and are drawing down their tax-free pension; patriotism only goes so far and you have to eat. Green card holders back in Australia approaching age 50/60 are handing them back.
Accountants are doing a great business including one who has a web site advising how to 'Avoid the Green Card Trap'.
But it is not just those nearing retirement who are impacted, any Green Card holder/US Citizen now is assessed by the IRS each year on their Australian Super Fund income - where the "income" is much higher than the Australian assessment and taxed more heavily. The sting is that, while any Australian tax is paid from the Fund itself, the Australian Government will not let funds to be withdrawn to pay US tax - so it comes out of the pocket.
It is not all gloom though; the US has an unique Visa for Australians (E-3) which has pretty good conditions. Accountants strongly recommend that Australians (holding Super Fund balances) follow this route and avoid the 'Green Card Trap'. Of course, this doesn't help US citizens!