Which is a myth. People in Columbus’s time knew the world was round all right, but they grossly underestimated the size of it and assumed that Asia was the approximate distance from Europe that North America is.
So what? The fact remains — Columbus was the one that ventured forth, took the risks, and transformed the knowledge into a plan of action. All the rest remained sitting in their stuffed armchairs — wishing they had a pipe to puff on, while they discussed “their” idea of a small round planet. They would have to wait until after Columbus “discovered” “India”, before they had any tobacco to put in that pipe. Columbus = Jobs. All the rest = armchair quarterbacks, academics, or commentators (with 20 20 hindsight).