Same here, been out of the States for 15 years and family have our own business. We've been paying taxes locally and filing tax returns yearly for the States. There's a minimum which one can make before they have to pay taxes to the US (about $70-80,000 a year individually).

For an average person or family, it's hard to reach this amount, and as said before you can write off taxes paid in a foreign country.

Though the main problem would be if you're registered as a Professional and individual business (contractor/consultant). Then you're liable for taxes in both the country you live in, and the US. I've been made a number of offers of work as a contractor and had to refuse (due to low pay since companies didn't want to hire employees only contractors, the fact I'd have to pay for all benefits, and also on top of that pay taxes on what ever I made).