It's generally a bad idea to say something can't or won't be done, especially in the realm of science and technology. The following are quotations that have failed to stand up to the test of time:

 

"I think there is a world market for maybe five computers." -- Thomas Watson, chairman of IBM, 1943.

"Where a calculator on the ENIAC is equipped with 18,000 vacuum tubes and weighs 30 tons, computers in the future may have only 1,000 vacuum tubes and weigh only 1.5 tons." -- Popular Mechanics, 1949

"I have traveled the length and breadth of this country and talked with the best people, and I can assure you that data processing is a fad that won't last out the year." -- The editor in charge of business books for Prentice Hall, 1957.