Why do even the experts miss the obvious?

Around this same time, a sixteen year old boy named Samuel Colt carved a new type of weapon out of a piece of wood and later had it made into a real gun. It was a .36 caliber, five-chambered revolving pistol with an octagonal barrel and a concealed trigger that dropped down when the gun was cocked. It could shoot five rounds in a matter of seconds. It was the world’s first revolver.
There was only one problem. No one wanted it. The U.S. government could see no practical use for it. Colt’s fledgling manufacturing plant went bankrupt in 1842, and he spent the next five years in poverty.