I still don't understand why they don't just buy a piece of property and build a large house on it. Is buying 4 different properites and building 4 different houses really cheaper than buying a piece of property and building a larger house?

In Utah, they weren't living in some large mansion type place and were able to do it, and with Robyn, all they are adding is another wife, 3 kids and a baby. They really couldn't find or build a house that was just a little bigger than what they had in Utah? Plus many of the older kids are leaving for college, so that leaves more room or less room to have to build.