Pellet's history is good, but he assumes the reader understands a lot of concepts that were around at the time such as reversible frames or reversible boxes (flipping the combs upside down for swarm control) and also the idea of a cut-down (contraction) vs unlimted brood nest ideas. At the time Pellet wrote it, a cut down split was a very common manipulation since virtually everyone was doing comb honey.
Everything is an oversimplification but here is mine:
Langstroth thought one ten frame deep box was enough for a queen to lay in and a colony to overwinter in. He was wrong as far as the North, but his hive caught on anyway and people made up for it by using two ten frame deep boxes in the North. Dadant was correct about how much room the queen needed, at least in the North, but his hive had less versatility. It was the right size for the North, but not for the South. Also, it just didn't catch on. My personal favorite of the time is the Heddon hive. He had the idea of managing bees by the box rather than the frame, but he was also obsessed by things like reversible frames, which were a waste in my opinion and probably contributed to why his hive did not catch on. The Dadant deep with 12 frames has the disadvantage of giving you little control over space and space management, in my opinion, is one of the most important aspects of beekeeping.
http://www.bushfarms.com/beesspace.htmI the end part of the reason for the differences were locality. If you look at how it shook out in the end, most northern states use two Langstroth deeps for the brood chamber. In the middle, places like Tennessee and North Carolina, they usually use one deep and a shallow or one deep and a medium. In the deep south, they usually use one deep for the brood chamber. So part of the problem is that there isn't a "right" answer as to how big the brood nest should be everywhere. There may be a "right" answer for a particular locality, but really I don't think there is even that. A small struggling colony struggles more when they have too much space compared to a strong established colony in the same locality...
http://www.bushfarms.com/beeslocality.htmI find it interesting how many beekeepers who were practicing the "contraction" method who were full time successful beekeepers. G. M. Doolittle, C.C. Miller, W.Z. Hutchinson...