I know a number of people who have immigrated from Scandinavian countries to the US, generally for high-prestige or high-paying work. If quality of life in Scandinavia was consistently higher than in the US, they wouldn't be doing this.

People also immigrate in the other direction. And more generally, it obviously happens sometimes that people move from one country to another with a lower average quality of life.

How are you extrapolating overall quality of life from some anecdotes of high-prestige or high-income workers? Seems like a fallacy of composition slipped in somewhere.