From a great post about Dennis Ritchie, that puts the magnitude of his contribution in perspective:
… A high-level, portable, efficient systems programming language.
How silly. Everyone knew it couldn’t be done.
C is a poster child for why it’s essential to keep those people who know a thing can’t be done from bothering the people who are doing it. (And keep them out of the way while the same inventors, being anything but lazy and always in search of new problems to conquer, go on to use the world’s first portable and efficient programming language to build the world’s first portable operating system, not knowing that was impossible too.)