But the evidence actually shows that a better returns can be had with stocks than cash (bills). Even with rates at 4%, stocks way outperform cash:
http://www.skepticmoney.com/wp-content/uploads/2011/05/1802-...
Putting cash into a bank is a poor way to save for retirement, if past performance is any clue.
The 'hardworking person' saving for retirement by stashing all his money in the bank may more myth than reality.
The majority of Americans have little savings, so the difference between 0% rates and 4% is immaterial if your expenses exceed your income.
http://www.gobankingrates.com/savings-account/62-percent-ame...
The problem is not that interest rates are too low, but rather people suck at personal fiance. But on the other had, the Paradox Of Thrift suggests that it's 'good' for the economy that too people don't save too much.
Those who have more wealth put it in stocks, bonds, or index funds. They seldom keep it in cash.