Here's a little ad from the Evening Public Ledger in Philadelphia (June 15, 1921).
I find it kind of odd to imagine the problems writers used to face. If you read the ad you can tell exactly what problems many fountain pens had (they could leak, needed to be refilled often, required repairs (!)). This remarkable pen--which had no such problems and could write for two miles without a refill (per bicworld.com, about as long as a modern-day ballpoint)--sold for a mere $4.00. (Per Historical Currency Conversions, that's about $50 in modern dollars.)
Most people don't even pay that for their touchscreen phone nowadays!
Yes, people could write in pencil, granted, but now many people write directly on their laptop. It's easy to edit without having to retype pages upon pages. Publishers don't have to manually typeset each page. Computers have become our typists and our typesetters. Well, I guess more accurately, most of us have become our own typists and some of us have become our own typesetters, using computers as a tool.
I wonder if authors' thought processes were different in the 1920s, knowing that what they wrote couldn't be rearranged so easily. How much harder must it have been to write back then!
Though they didn't have the Internet to distract them back then, so maybe it is kind of a wash.