Income early in one's career is typically lower than incomes later in one's career. So even if retirement income is lower than final career income, there's still a good chance it's greater than entry-level income and would be taxed at a higher rate. You've also got to keep in mind that taxes may eventually rise. America's top rate today is much, much lower than the top rate historically--no reason to believe it couldn't swing back the other way.
oh i see the pattern like someone making $50k a year to start, but rises to $150k by end of career and whom is planning for a retirement income of the average (100k)... Then a Roth is a good deal when making $50k (at the beginning) and regular is better when making $150k (at the end)...
