In the 1950s there weren't any alternatives to the US. Europe and Asia were rebuilding from WWII. Central and South America weren't nearly as developed as today. Places like Singapore, Taiwan, and Korea were extremely poor. The english language wasn't as popular internationally. Intercontinental communication was expensive and low bandwidth. Travel was much more expensive. These communication and travel costs made investing in foreign ventures was a very risky endeavor. Nowadays, it costs nothing to video chat with people on the opposite side of the planet. And foreign investments are no longer the crapshoot that they used to be.
It's much, much easier to live and work in a foreign country today. And it's only getting easier as technology improves.
> Governments invest a lot in their country, their citizens, education, a healthy market, etc.
Do they? I find that most people are successful despite governments, not because of them. For example: One of the schools I went to as a child was structurally condemned while I attended it. The water wasn't fluoridated, so my parents had to pay for fluoride pills to protect my teeth. I don't feel beholden to the government I live under anymore than I feel beholden to my employer. My employer has taught me valuable skills, invested in equipment, training, and pays for health care. Does that mean I should pay dividends to them after I leave? I don't think so.