The 401k started off as a tax dodge for the rich in the 1970's. The light bulb went off in the collective asset managers brain in the 80's. It was driving them nuts that an entire retirement fund only had one manager for thousands of people. Shouldn't that be thousands of fees for thousands of management accounts and no strings attached! After a little congressional prestidigitation the defined benefit pension was destined to follow the Dodo. And the fees kept multiplying. As a defined contribution, why not? There are no penalties nor, more importantly, structural pressure to minimize fees.