The problem is how we tax investment gains. Over the past 80 years, the average annual return on Treasury bills (a proxy for savings accounts) has been 3.7 percent per year. Inflation, meanwhile, has averaged 3.1 percent per year. This combination has produced a "real return" of a paltry 0.6 percent per year. If you got to keep that 0.6 percent, you might still have an incentive to save: A $616 real gain on $10,000 in 10 years wouldn't be much, but it would at least be $616 more than you have now. Unless you're so poor that you're exempt from taxes, however, or so flush that you can afford to lock up cash for decades in a tax-deferred annuity or retirement account, you won't be keeping that 0.6 percent. You'll be giving all of it—and probably more—to the government.