If there is one thing the past can teach you it's that predicting the future is a mugs game. Classic quotes of how incredibly wrong people can be:
"The horse is here to stay but the automobile is only a novelty—a fad." – The president of the Michigan Savings Bank advising Henry Ford's lawyer not to invest in the Ford Motor Co., 1903.
Good old barking mad Lord Kelvin, wrong about most things except temperature:
"X-rays will prove to be a hoax." – Lord Kelvin, President of the Royal Society, 1883.
"Heavier-than-air flying machines are impossible." – Lord Kelvin, British mathematician and physicist, president of the British Royal Society, 1895.
"Radio has no future." – Lord Kelvin, Scottish mathematician and physicist, former president of the Royal Society, 1897.
"There is nothing new to be discovered in physics now; All that remains is more and more precise measurement." – Lord Kelvin, speaking to the British Association for the Advancement of Science, 1900.
"Who the ****** wants to hear actors talk?" – H. M. Warner, co-founder of Warner Brothers, 1927 on the future of cinema with sound.
"A rocket will never be able to leave the Earth's atmosphere." – New York Times, 1936.
"Television won't last because people will soon get tired of staring at a plywood box every night." – Darryl Zanuck, movie producer, 20th Century Fox, 1946.
"There is no reason anyone would want a computer in their home." – Ken Olson, president, chairman and founder of Digital Equipment Corportation (DEC), maker of big business minicomputers, arguing against the PC in 1977.
(Bill Gates also said something about not being able to imagine anyone ever wanting more than 64k on a computer for home use but I cant remember where I read the quote)
"Space travel is bunk." – Sir Harold Spencer Jones, Astronomer Royal (UK), 1957 (two weeks later Sputnik orbited the Earth).
"We are probably nearing the limit of all we can know about astronomy." – Simon Newcomb, Canadian-born American astronomer, 1888.
My personal favorite:
"Sensible and responsible women do not want to vote." – Grover Cleveland, U.S. President, 1905.