I had forgotten that long era when inflation was greater than zero and short-term rates were being held down by the Fed.

That's far from the only instance. Since 1950, assuming a fairly arbitrary 1/3 income tax on nominal interest, you'd have had a 59.4% chance of losing purchasing power holding a 90-day T-bills after tax and inflation. Real rate of return after tax annualized, averaged across all start dates, -0.777%.

Part of the reason that seems dire is that during periods of high inflation you pay tax on the nominal gain, not the real gain. The real after tax return has been positive most of the last couple of years, but that's not the general rule.

Speaking of inflation, here's a fun tidbit not a lot of people know. The average non-supervisory US worker's after-tax pay has gone up more since 2019 than inflation or groceries or average rent. At the moment annual grocery inflation and rental inflation rates (2.5% and 3.5%) are both below long-term averages. So why all the inflation angst? The number on the average food price sticker has gone up a lot, which people REALLY notice, and really hate. But the number on the average pay slip has gone up more, so less of the income is going to food, not more. Same for rent, or CPI overall: incomes have risen more than general inflation.

Jim