It's been a third of a century since benefits consultant Ted Benna helped bring attention to a new but obscure provision of the federal tax code known as 401(k), which was meant to provide a tax break for folks with deferred income. As co-owner of the Johnson Cos., Benna was redesigning the retirement program for Philadelphia-based Cheltenham National Bank when he realized that the provision allowed employers to use salary deductions as tax-deferred contributions to employee retirement plans. To be sure, Benna was not the only one looking at the possibilities afforded by the 401(k). Among other firms, healthcare-products giant...