Think of CD as standing for Constantly Diminishing. The stability of CDs does not translate into long-term security. Viewed from this perspective, the government-guaranteed savings plans are not wise, conservative or responsible. Even when interest rates are high, savings is a bankrupt investment policy. For instance, many savers fondly look back over the last 20 years of high interest rates.
Interest rates are high during periods of inflation.
A progressive tax eats away more at the higher nominal rates of return. Later we will examine how inflation ravages a fixed return over time. If a saver attempts to live off the interest on his nest egg, the results are catastrophic over time. He better hope not to live very long. So if you just want to keep up with inflation, you can accomplish that limited objective with debt instruments, but not much more.