Under normal conditions, when your economy becomes less competitive, your currency gets depreciated, increasing competitiveness.

Unless of course everybody is forced to buy your currency to get an essential resource. This causes: - the currency to maintain value better - puts you in position of other countries having to maintain a trade surplus with you so they can actually purchase said resource - the oil producers end up with great amounts of your currency, which they have to spend, getting a political foothold in your country.

Petrodollar almost certainly was devastating to US economy. And like most resource curses, it's like a drug - you need to stop taking it to get better, but it will hurt as hell.