On a typewriter. Even more telling, he's still in print. Still, at some point, he knew the story was finished and sent it off. For me, that point is when I can't find any more reasons why my story could possible be rejected. I'm a ruthless critic when it comes to my own work, and if it is still rejected, I will set it aside to revise another day.
Revision is a challenge, but also an opportunity.
After all, nothing is chiseled in stone, unless one is in the monument engraving business. Even then, mistakes are made. I have a friend who never revises, doesn't believe it is necessary. When he doesn't sell a particular story, he files it away and goes on to the next one, never looking back. I find this a terrible loss.