CMV: It makes sense for me as an American to move abroad permanently if I can find online work and be paid in USD

Not to get overly anecdotal, but I (21M) am approaching a point in my field of work where within a few years, I will likely be able to work completely remotely, and because of this I've thought a lot about the possibility of moving abroad on a USD salary.

For the record, this is not one of those "Trump is bad so I'm leaving the United States!" rants. I don't care for the guy, but who gets elected President here has zero bearing in my decision to live in the U.S. or abroad. All things considered, I love America, and I think we probably have the best and most reliable system of government on the planet. However, it's expensive to live here, and the power of the dollar is stronger literally everywhere else.

A few ideas have crossed my mind, I've heard a lot about Mexico City as a destination for American expats (and it's becoming popular enough for online workers that there's even small areas of the city now that primarily speak English), South Africa has the lowest net cost of living of any English speaking country so perhaps that could be an option too.

Granted this is all conceptual so take it with a grain of salt, but the broader point is that these are all places I've visited personally and as I contemplate it, if I get to a point where I'm making money remotely I don't think I'd ever have a problem with living abroad, and if it's so much cheaper outside of the country, I suppose why not?

Why not though is the essence of the view. The "me" in this scenario is almost irrelevant, because the concept of being paid in USD remotely while living abroad certainly isn't my idea, there's countless people doing it already. So approaching this more conceptually, talking to any American who is both working remotely and able to live outside of the country, why should they stay? Change my view, why is accepting the higher cost of living in the United States worth it?