In my school curriculum here in Vienna, this was very specifically taught in history class.
I'd be surprised if they could average more than 2 pages / minute? Which for 1000 pages is still a full days work.
I was involved a bit in printing manuals in the 1980s. The cost of printing 100 copies vs 1000 copies was pretty much the same. The delta is the cost of the paper.
Random online estimates suggest 4 hours to typeset a page and 200 pages an hour. So 800 copies.
I think this makes my point that on a Gutenberg press printing the already typeset page still wasn't that fast.
And inevitably, efforts were made to improve the efficiency of the printer.
Anyway, feels like this is no longer a productive discussion.