It's a financial accident. After World War 2, the USA was the least damaged country on the winning side, so it got to own the western world's financial system. It used that [exorbitant privilege](
https://en.wikipedia.org/wiki/Exorbitant_privilege) - possibly unintentionally - to import money and export inflation for decades, keeping the exchange rate skewed in its favor.
People aren't coming for the scenic canyons, they're coming to get some of that USA money, so they can be on the benefitting side of the skewed exchange rate, instead of the losing side. Many of them exchange part of their salary for their home currency and send it home, in quantities that would be impossible to accrue if you did the same work in that country.