You might be on to something, but high earners (ie those with influence) absolutely love 401K's. It is a great way to save tax free money if you have lots of discretionary income. Plus 401K's feed Wall Street a large investment stream to make money. So if the left wants this it will be a tough road as the left has lots of rich people.
Clintons’ Secretary of Labor, Donna Shalala, wanted to “capture” all the unpaid taxes on 401k’s since her first day in office. The left has been salivating to get their grubby filthy hands on 401k’s from the day Reagan instituted them.