That's not how it works. You pay last-dollar taxes on the money that would otherwise go into the 401k. You pay first-dollar taxes it when you withdraw at retire

That's not how it works. You pay last-dollar taxes on the money that would otherwise go into the 401k. You pay first-dollar taxes it when you withdraw at retirement. The first-dollar taxes are lower up to the tax bracket you'd otherwise be in if you didn't contribute to the 401k, unless you have additional sources of retirement income.