There is absolutely no significant number of Americans who left without ties to other countries. I find it rich that Americans who leave the US call themselves “ex-pats” instead of “immigrants”

There’s over 1/2 million former Americans living in Canada or the UK which doesn’t require learning a foreign language. You really can’t make those kinds of sweeping statements about populations that large. Many Americans without any prior connections fled to Canada to avoid the Vietnam war for example and then made a home there.

Brit’s will also call themselves expats. https://britishexpats.com/forum/ ditto Canadians https://www.expatden.com/global/canadians-living-abroad/ Also, the US imposes taxes on Americans who leave until they renounce their citizenship on the upside they still get to vote. It’s an unusual relationship to your former country.