and just what were your AGI and deductions? if you dont make that kind of income then you wont be paying that kind of taxes. i am not saying it is common for retired people on this board to pay that kind of taxes but then they arent making that kind of money either (and of course it makes a difference how you get that income, whether it is tax favored (like LTCG and dividends) or not favored (like interest or STCG)). just becauase you arent making that kind of income doesnt mean someone else isnt. remember the high interest rates of the early '80s? if someone investing a million back then was concerned about investing in the stock market so s/he invested in bonds (and other loan type instruments) s/he could have been pulling down 16% interest on the million and thus been paying that amount in taxes (especially since tax rates were higher). and just because you dont get that kind of a taxable return on your money now doesnt mean nobody does.
yes i picked an extreme example (16% taxable income) to make my point but that doesnt mean it is invalid, instead it just shows off my point. what if you were getting 12% instead of 16%?.
Ok, I went back and looked at some returns after my transitions years (99-2000) my AGI ranged from 80K-125K and the tax ranged from $5,400 to 12,400. So roughly 7-10% and of course this year with my AGI dropping to 50K my tax dropped to $116 so I actually paid negative taxes. I didn't get the $200 ($300?) stimulus check but Turbo Tax says I now qualify. Deductions ranged from the standard deduction to around 15K. (mortgage interest, property taxes, contributions)
Of course most of my income is qualified dividends, MLPs, some tax exempt bonds, and capital gains. But it isn't by accident that my IRA consists mostly of bonds, REITs, and a couple of non-dividend stocks like Berkshire.
Where as my taxable account has only a GNMA fund and smattering of money markets/CDs that is taxed at regular income rates and most everything else is index funds, dividend paying stocks which are taxed lightly
My point is that retirees often overestimate the amount of taxes they owe in retirement. I know I did. I found I have far more control over the taxes I pay as retiree than I ever did while I was working. If want to lower my AGI to take advantage of special tax breaks of using saving bonds to pay for educational expense, I just hold off realizing capital gains that year.
So while your examples are possible I just don't think they are very likely, if you do even a 1/2 way decent job of asset location with your portfolio. You just wouldn't owe $36,000 in taxes on a million dollar portfolio and thus be left with only $4,000 to spend from your 4% SWR. It just ain't going to happen. Even those 16% 30-year bonds from the 70s have matured LOL.
Now as to your other point that preparing your portfolio for retirement can involve a great deal of taxes. I completely agree, in fact during my transition years I paid hundreds of thousand in taxes, due exercising stock options, selling my portfolio of high-tech stocks and buying bonds, and truly hellish experience with the byzantine world of AMT. I would certainly recommend that you base you SWR on your assets after you pay your taxes.