There's a good statistical analysis of the declining work ethic in some classes of white Americans in Charles Murray's book Coming Apart. I recommend the book.

There's a good statistical analysis of the declining work ethic in some classes of white Americans in Charles Murray's book Coming Apart. I recommend the book. It's not directly about this mainly, but the work ethic decline is statistically identifiable and localizable to a specific class of white American (who are also a class that people like you and I have essentially zero personal contact with).