The rest of Chapter 7, Affordable Houses for the Common Man, 124 - 137(The sections on Balloon Framing, Cheap Land, High wages, TheProvision of Urban Services, Individual Effort and Home-ownership, and The Process of Suburban Land Conversion.)8, Suburbs into Neighborhoods, 138 - 156Don’t lose sight of the forest for the trees. The most important think to understand is that it was a combination of factors which made suburbia affordable for middle class persons. We’ve already seen that cheaper transportation opened opportunities unavailable before. If one thinks about the slow and laborious process of making houses prior to the invention of the 2x4 and the machine-made nail (you saw some of this in the video from the Weald and Downland Museum), one realizes that there was no way to house large numbers of people in individual houses on individual plots of land without technological innovation intervening. Imagine how much it would cost to build Mr. Blandings Dream House if all the nails were individually made by blacksmiths.
Here, the important thing to recognize is that there are multiple ways to measure size of communities. Perhaps the one we think of most often is population, which we can determine by simple count. But area is another measure... the number of square units (miles, kilometers, etc.) included in the political unit in question. A third is density of population (population divided by area). Be aware that it is the second which is being explained in this chapter. The process is annexation. The reasons for it and the reasons against it are the subject of this chapter. The last paragraph is rather ominous: 
Houses for the Rest of Us