[laurentl]

Define "middle class Americans"? Hard to give a precise answer otherwise.

A few (other) explanations:

* QoL is hard to be rational about, and is something that (I think) has to be experienced first-hand. European salaries are most probably lower for comparable jobs (they certainly are for high-wage workers) but pack more punch because of better social benefits and, depending on where you live, lower CoL. However it can be hard to convince yourself that 40 k€ in Spain affords you a better QoL than 80k$ in California unless you've experienced both. I mean, 40 is much less than 80, right?

* the "American Dream" is still a big part of the American (and global, for that matter) psyche. I would wager most Americans think the US is a place to emigrate to, not from. I don't know if many middle-class Americans would spontaneously envision emigrating to Europe. This is probably even more true for descendants of recent immigrants: if your family struggled to get to the US, why would you consider leaving?

* Ability to live abroad, in particular mastering a foreign language well enough to live and work in the country

* I'm not sure how well employability travels. You can work as a developer in just about any country but I think this is an exception. A medical diploma does not transfer well between countries (e.g. you probably need to start again as an intern, re-take exams, etc.), neither does a law diploma. More "middle class" jobs will have similar barriers to entry. E.g. if you're a plumber in the US and move to Europe you have to deal with different construction codes, installed base, local habits... Same thing if you're an auto mechanic: different car manufacturers, different regulations, etc.

[onecommentman]

Americans in HCOL locations have a third option to Europe, and that is the rest of the United States. RoUS provides close to a factor of two cost savings, you speak the language, same level of bureaucracy, close (enough) to family, similar enough culture to be comforting but with enough differences to make it interesting (desert Southwest, Deep South, New England, Florida Keys, Midwest, Appalachia, PNW, Intermountain West, Alaska, Hawaii, Texas…). Canada, Mexico and the Caribbean a drive/cruise away and provide their own long term opportunities. The United States is much more culturally diverse than the few places Europeans choose to visit for extended stays.

The United States offers a political stability that Europe has yet to demonstrate long-term (cherry-picking here, but let’s say over the last 150 years, two modern lifetimes). The comic opera/snuff film of European wars in the 1900s did provide 104366 young Americans with a forced permanent relocation to Europe. Not a positive memory for Americans.

And Americans can develop a community in the United States that achieves many of the charming aspects of European life. Americans have both the freedom and gumption to do that, if they wish. Americans are not limited by land nor resources, intellectual, cultural or otherwise, nor vision.