Felix points out the downsides:
[T]he 401(k) is a way for both your government and your employer to disown you, and to leave your life savings to be raided by the financial-services industry and its plethora of hidden and invidious fees. The well-kept secret about old-fashioned pension funds is that, for the most part, they’re actually very good at generating decent returns for their beneficiaries. They tend to have extremely long time horizons, and are run by professionals who know what they’re doing and who have a fair amount of negotiating leverage when they deal with Wall Street. Savers are always strengthened by being united: disaggregating them and forcing them to take matters into their own hands is tantamount to feeding them directly to the Wall Street sharks.
The Dish 