"There Is No Reason for Any Individual to Have a Computer" — Ken Olsen (1977)

Ken Olsen's 1977 assertion that no individual needs a computer is a legendary blind spot, even worse than the average tech executive's skepticism of the era. As DEC's founder, he dismissed personal computing just as the PC market was about to explode from 0 to over 200 million units by 1999. This miscalculation directly contributed to DEC's decline, with the company sold to Compaq in 1998 for $9.6 billion—a fate that underscores how his failure to see the future proved 30% more costly than other mainframe makers' missteps.