Yes, the key here is that there's a $18k max on contributions to your 401k, so it's very unlikely that you'd save enough to retire in 10 years just by maxing out your 401k (unless your spending is really really low). So in addition to maxing out your 401k, you're going to have to be doing some savings in a taxable account, and that money will be key for getting you through the early years. For instance, let's say you're planning to retire at 40, and your annual spending is $25k. Your withdrawal strategy might look something like this:
Age 40: Retire! Roll your 401k into an IRA, and roll $25k from the traditional IRA into a Roth IRA. Spend $25k from your taxable account. Pay taxes on the $25k you rolled over from the traditional to Roth.
Ages 41-44: Repeat as above. Spend $25k from taxable, roll $25k from traditional to Roth, and pay taxes on the $25k you rolled over
Ages 45-54: Now that your first $25k installment in the Roth has been sitting there for 5 years, you can pull it out and use it. So no need for the taxable account any more, just spend $25k from the Roth each year, and roll a new $25k in each year.
Ages 55-59: Continue spending $25k from the Roth, but no need to roll new money in anymore as you'll be eligible to pull from the traditional IRA by the time the money 'ripens.'
Age 60+: You've reached traditional retirement age! No need for the Roth or the taxable account anymore, you can just start pulling directly from the traditional IRA.
So, basically, you just need enough money in a taxable account to pay for your lifestyle for the first 5 years of retirement, and from then out, you'll be able to pay out of your 401k money by rolling it through a Roth IRA pipeline.