There is some truth to that. Different parts of the U.S. are vastly different in wealth, and most people have very little conception of what norms are outside their peer group, both their geographical peer group and their sociocultural one. For example, living in Silicon Valley and working in tech, you might think that $100k+ is a common white-collar salary, something that most educated professionals would make—if not as starting salary, then at least after a few years.
What percentage of American salaries do you think are $100k+, though? I've heard people guess as high as 20-30%. Some people, both Americans and foreigners, seem to imagine it as this super-rich country where everyone is making those kinds of salaries. But the real number is 7%.
(About 20% of American households do make 6 figures, but most of those are two-income families that are adding together two 5-figure incomes, e.g. husband and wife each making $60k.)