But you only pay taxes at the rate you take it out. And since many spend less to live on in retirement, you gain a lot by lowering your tax bracket.
Whereas a Roth, you are taxed at your income rate.
Plus, there are limits on who can actually use a Roth. Sure, most of the middle class will never see that, but that does leave people who earn up to the 401k limit as the ones who really are holding the tax burden bag.
A far better way to raise income taxes is to balance the taxes WRT source. Make unearned income equal with earned income. That will generate billions in tax revenue. Make actually working for your money the goal again. But this will never happen, as it puts more burden on people who make over $1M a year. As if they need to pay less to live on.