Interestingly, this article in The Boston Globe suggests that the typewriter promoted the rise of the practice of revision, but that the computer may be killing it:
In a new book, “The Work of Revision,” Hannah Sullivan, an English professor at Oxford University, argues that revision as we now understand it—where authors, before they publish anything, will spend weeks tearing it down and putting it back together again—is a creation of the 20th century. It was only under Modernist luminaries like Ezra Pound, T.S. Eliot, and Virginia Woolf that the practice came to seem truly essential to creating good literature.
What caused these writers to put their faith in revision as the key to good literature? In part, it was the philosophy of Modernism—the idea that a novel or poem should challenge the reader, break with tradition, and, in the words of Pound, “Make it new.” But Sullivan, who belongs to a new wave of scholars trying to understand literature through the physical and historical realities of its creation, finds that our value of revision was also driven by something else: the typewriter.