Well the 401k has some tax benefits as well, as long as you keep your withdrawals to a reasonable level, so I think you should still make use of it. But the higher your annual withdrawals and balance get, the less tax benefit you will receive.
For example, when you are working and contributing to a 401k, you save yourself from paying 28% or 25% tax on your contributions, and that extra money saved is also growing and compounding in your investments. Then when you take withdrawals, you can make use of:
$23,100 standard deduction and personal exemptions = tax free
then AFTER that:
$18,450 = 10% tax bracket
$18,451-$74,900 = 15% tax bracket
So pause here, and let's say you withdraw $98,000 from your 401k, you will pay $10,312.50 in taxes which is 10.5% of $98k. That doesn't sound too bad, considering that you originally saved 28% or 25% tax when making your contributions.
However, you should also take into account taxation of your Social Security benefits. When your AGI + 1/2 of your SS benefits exceeds just $44k when married, then 85% of your SS benefit will be taxed. So say each spouse receives $30k SS, then they will have to add $51k to their taxable income! I would stack this first at the bottom of the tax brackets, so I see it as the SS using up all of your standard deduction, personal exemptions, all of the 10% tax bracket and some of the 15%. Now your 401k withdrawals sit in the 15% and 25% tax brackets. Let's just say the effective tax rate on the 401k withdrawals is around 20%, which is now not looking so great compared to the 25-28% tax rate you saved on the contributions.
Furthermore, if you max out your 401k every year, you will accumulate a very large balance in there. Consequently you will have to take very large annual withdrawals, some of which will sit in the 25% and 28% tax brackets to push up the effective tax rate and erode your tax benefits even more.