Well, Luke, I was introduced to the concept in an anthro class about 27 years ago, so I am not the guy to ask about texts.
The point in this case is that shooters two centuries ago had a different set of conditions, resources, priorities, and preconceptions. Perhaps in certain ways they were less open to innovation. Perhaps, to them, the concept of a faster second shot, patched, wasn't such a priority. We can research all we want, but after a certain point we can only speculate.
Not being a reenactor, I find my loading block quite convenient.