Few today remember the frustration of typewriters, where speed was
a goal, but the faster you went the more mistakes you made.
Correcting a mistake in 1945 was a painful process, involving some
"whiteout," or other messy, time consuming process. So each mistake
produced a wince, and not until the error correcting ribbon came along
and acknowledged the reality of typing mistakes did things improve much.
Of course being caught with a bottle of whiteout in a typing class was
bad for your grade.
The introduction of the IBM ball typewriter in the early 1960s at least
prevented a tangle of letter hammers from resulting when you attempted
to go fast.
But after a month or so most people could type passably well, and slug it out on a cranky home machine when necessary. Most people's typing skills now serve them well on their PCs, where mistakes are but a minor nuisance.