That sounds more like FIRE / geographic arbitrage than expat in the traditional sense.
What people often mean by a "true expat" is something completely different: someone sent abroad by their employer, usually with a generous expatriate package (home-country salary, local allowances, housing, private schooling for children, etc.)
More broadly, though, expatriate simply means someone living outside their native country. Ex means "out of", and patria means "native country" or "homeland". It's that simple.
So the word itself isn't limited to wealthy retirees or corporate transfers. All immigrants are expatriates, although not every expatriate is necessarily an immigrant.
What people often mean by a "true expat" is something completely different: someone sent abroad by their employer, usually with a generous expatriate package (home-country salary, local allowances, housing, private schooling for children, etc.)
More broadly, though, expatriate simply means someone living outside their native country. Ex means "out of", and patria means "native country" or "homeland". It's that simple.
So the word itself isn't limited to wealthy retirees or corporate transfers. All immigrants are expatriates, although not every expatriate is necessarily an immigrant.