In some cases it started off as a form of wage restraint in the dark days of the 1990s: companies cut basic wages and employees hoped that performance-related pay might makeup the difference, which it did not always do.
Granted George Miller (D-Calif.) took up the cause and in 2007 introduced a bill whose basic premise was to make clear to employees and employers on quarterly statements how much money employees were paying in 401(k) fees.