What are some of the worst wrong predictions ever made in history?

A few that were slightly off:

“The telephone may be right for our American cousins, but not here because we have an adequate group of messenger boys.” Editorial in The London Times

Michigan Savings Bank told Henry Ford’s lawyer, when the newly incorporated company applied for a loan, “The horse is here to stay, but the automobile is only a novelty, a fad.”

The New York Times reported that a brain specialist issued a severe warning to automobile manufacturers: It remains to be proved how fast a brain is capable of traveling…if it cannot acquire an eight miles per hour speed…it is running without the guidance of the brain and the many disastrous results are not to be marveled at.

JP Morgan told his dad that he had met Thomas Edison and was interested in financing his new company, General Electric. Papa Junius was apparently a bit old school, “Electricity is just a fad”. Fortunately, JP did not listen to his dad.

Alexander Graham Bell had the the patent for the telephone, but wanted money instead. He offered Western Union the rights for $100,000. Its president was offended and sent an internal memo, “It’s a toy. The idea is idiotic.”

And finally, the master of wishful thinking, Bill Gates, who obviously never looked at Quora when he said, “Spam will be a thing of the past in two years time”.

“The year which has passed has not, indeed, been marked by any of those striking discoveries which at once revolutionize, so to speak, the department of science on which they bear.”

Thomas Bell, 1858 reviewing the scientific studies of the year including Charles Darwin’s Theory of Evolution.

“We will not see a crash in our time.”

John Maynard Keynes, 1927 two years before the Wall Street Crash that started The Great Depression.

“He does not possess significant leadership qualities.”

Officer report on Corporal Hitler, 1918 on reason for not promoting the decorated NCO to officer.

“I believe it is peace for our time.”

Neville Chamberlain, 1938 after the Munich Agreement with Hitler. World War Two started a little more than a year later.

“We are not about to send American boys 9 or 10 thousand miles away from home to do what Asian boys ought to be doing for themselves.”

Lyndon Johnson, 1964 a month before his landslide electoral victory. He’d end up deploying the first American combat troops to Vietnam a couple months after his inauguration. There would be ~600,000 American soldiers in Vietnam when he left office.

“What we may be witnessing is… the end point of mankind’s ideological evolution and the universalization of Western liberal democracy as the final form of human government.”

Francis Fukuyama, 1992 on the fall of the Soviet Union. The rise of Putin would dispute this statement.

“Six days, six weeks. I doubt six months.”

Donald Rumsfeld, 2003 on how long the Iraq War will take. He would leave office three and half years later at the height of the Iraq War. After a temporary cease in hostilities, the Iraq War flared up again in 2014 and still has not ended.

“Everyone’s always asking me when Apple will come out with a cell phone. My answer is, ‘Probably never.’”

David Progue, 2006 doubting Apple would release an iPhone one year before its launch.

“The truth is no online database will replace your daily newspaper, no CD-ROM can take the place of a competent teacher and no computer network will change the way government works.”