It's amusing to read that sentence juxtaposed with your previous comment "[One flaw with the Golden Age was]... that writers were paid for volume, not content..."
Consider 'Golden Age' books from Asimov and Heinlein as compared to their later works. The earlier work was much more concise.
It was concise because that is why they survived. Most authors tried to crank out voluminous filler and the editors would slash and burn it, then pay them for what was left over.
This was one of the reasons suggested why L. Ron Hubbard got into the religion business, because he couldn’t cut both quality and volume in his writing. It was just too much work.
“If my doctor told me I had only six minutes to live, I wouldn’t brood. I’d type a little faster. “ - Asimov