It's not clear from the article that Krugman is calling for a 91% top marginal rate, but if he is supporting confiscatory rates, he's just wrong.
High tax rates in and of themselves will not address the level of wealth inequality present today in the USA. Rates are TOO LOW for under 100k. Capital gains rates are too low. Carried interest is a farce. 35% is plenty high for wage earners. Couple that with state taxes and you could be looking at close to 50% before sales tax, property tax, and all the other hidden taxes, like in our telephone and cable bills and tolls, etc. Why should the state take 1/2 of a good earner's paycheck? They should not. And all this talk about the lazy takers is a red herring: welfare,unemployed, and food stamp recipients are not a punishing part of the budget. Its Defense, Medicaid, and Medicare that are too thirsty for public dollars. And it's a warped tax code that allows for inequitable taxation private and corporate.
We have a 14 trillion dollar GDP and Federal, state and local expenditures are 7 trillion. 50% of our economy is the government at one level or another. Something to think about. I wonder how that stacks up against the 1950s?
Krugman's portrayal of the average corporate executive living in a suburban house in the 1950s may be correct, but it wasn't because of high tax rates. Corporations then didn't have a stock market with trillions in equity from America's retirment and pension funds. They have it now and they rape it mercilessly with shameless stock option grants.