The thing that may have set it off prior to 1936 is the depression. Thus, larger farms were assembled by the institutions simply doing foreclosures. Presumably, these farms were not always subdivided when the institutions sold them. We all know that this is no longer true and Ireland is currently on a fast track. Now give me a break on urban concentration.
Housing is associated with diffusion of property ownership.
This is the whole point of subdivision. Thanks for your comments, Peter. Rather, it is a question of fact. However, there are some indirect sources. They are not a modern invention.