I think flu has been suggesting this possibility or a similar one.
The similar idea he’s suggested is that your post retirement taxable income is high enough that you pay higher taxes on the RMD of your IRA/401k than you would have at the time you were earning it. I think he’s pumping money into Roth’s for this reason.
I am crappy at prognostication. Especially when it comes to future tax policy. I’m concentrating more on how to reduce expenses in retirement (paid off mortgage, etc) so what little money I have after taxes will cover my expenses.