And replace them with what exactly? Business crippling defined benefit plans? BWAH!
There are problems with 401k's, including the fact that many are run by firms sucking huge fees from the participants. The model 401k plan is the Thrift Savings Plan (www.tsp.gov) run by the federal gov't for gov't employees. If I was president, I'd require this be an available option for every employee.
Another issue is that less than 80% of employees participate in available plans.
http://www.usatoday.com/money/perfi/retirement/2007-10-22-401k-automatic-enrollment_N.htm