This is true but the situation is substantially more complex than you suggest, including things like PFIC treatment of retirement plans in the foreign country (where you need to pay unrealised capital gains every year), differing treatment on capital gains of housing, Affordable Care Act penalties if you're in the US more than 30 days. Not to mention any use of the foreign tax credit means you need to calculate AMT.
Not to mention none of paperwork you need is nicely collected and presented in US Dollars for you. God forbid you live someplace like Australia that uses a July-June tax year.
I have to file my US taxes every year and the "cost" is usually $400 to $800 to hire a tax preparer who knows what they are doing and takes a fair amount of my time every year.