Maybe that was true 40 years ago. Nowadays a median middle class natural-born U.S. citizen is a fat type with an old SUV, living in a cardboard house and getting maybe $60k a year. Such a quality of life is within easy reach of every person in the world except maybe totalitarian societies like DPRK (which are very rare) and extremely dilapidated sub-Saharan Africa countries, given he has some brains and will to work hard. We live in a global world.

I don't even tell many people in places like Eastern Europe enjoy better quality of life right now, with maybe somewhat less cash - in safe, walkable, well-designed cities, with better food and environment and less spoiled societies with a strong demand of democracy (nobody wishes to return to Soviet era and every government looking like doing so will be thrown out quickly).