Buried inside many 401(k) plans are fees charged by the plan sponsor that are often in addition to what many would consider the transparent information available. These fees are not often known to the 401(k) investor at a glance.
Fiduciary responsibility remains a difficult ideal to litigate. "Captive" investors may simply have to deal with higher fees in the short-term until there is some ruling supporting comparisons. Or, as many in the investment community hope, the markets will return and these concerned investors will simply forget how much they could have made with lower fees as higher return offset the losses.
Paul Petillo's full article on fiduciary responsibility can be found here.