I'ts an empirical guess, and may or may not be accurate. But it is not even close to being a "stretch," and I cannot off hand think of any group of workers in respect to whom there is a wider gap between their pay and the immense 'pile' of wealth their labor generates. No description of a group of people can tell you anything about whether they are exploited or not, because that depends on aration, between the value of their labor power and the value they create. Barry Bonds salary 8is mniscule in comparison to the immense wealth for baseball owners, tv corporations, newspapers, madison avenue, etc that his labor has generated.
Carrol