The Pew study looks at household income. I guess that is one way to look at it, but it never struck me as a reasonable model. When you look at wages, the story is far more concerning. Focusing on wages surfaces the fact that households have broadly gone from one income to two since the 70's. Modeling based on household income understands the depressing of wages as a loss of leisure time. I'm not saying it's wrong, just an odd perspective.