It really depends on how "standard of living" is measured in the first place. I live in Europe and make top 5% percentile income, live a pretty decent life that doesn't require a car, in a very energy-efficient apartment. In the US I would likely not have that option, would likely be forced to have a car, would have less vacation days, would have to navigate a nightmarishly complicated healthcare system, and survive some school shootings. Yes, I would make more money, potentially live in a bigger house, but it is debatable if that would automatically be a higher living standard.

EDIT: Also worth mentioning: for a huge chunk of Americans, living an European standard of living would be a huge improvement.