While some very positive economic signs have popped up in the past month, pessimism — and in many cases downright doom and gloom — continues to hover over the U.S. economy. But author and Wharton professor Jeremy Siegel says that the bears are off-base, and that those who say stocks are dead are repeating a mistake others have made throughout history.

In his latest column for Kiplinger’s magazine, Siegel points to a 1979 BusinessWeek cover story titled, “The Death of Equities”, in which the magazine said wild inflation had made the demise of stock investing a “near-permanent condition”. Only three years later, however, an 18-year period began in which stocks returned an average of nearly 20% per year.

“Pessimism is as rampant today as it was in 1979 and, once again, it is misplaced,” Siegel writes. “The specter of inflation has been replaced by fear of a trio of other dire prospects: deflation and financial collapse, the long and painful unwinding of an economy that has gorged on borrowed money, and the prospect of millions of baby-boomers selling their stocks to finance an increasingly bleak future.”

Siegel says the doomsayers are showing the same shortsightedness BusinessWeek did back in 1979. He notes that studies — including his own — show that stocks have a remarkable long-term track record of being the best long-term investment vehicle. He also says that productivity growth — not debt levels — is what really drives economic growth, and productivity been increasing over the past decade. And, he says, his research “has found that rising incomes in Asia and elsewhere can generate enough savings to absorb the boomers’ asset sales without significantly depressing prices.”