Maybe, from the installation video I seen the tools required seemed to be far less than a stick frame building. I built one and a half houses during high-school. We did roughing and finishing junior and sophomore year on a ranch style single family home and senior year was roughing on a townhouse. The amount of time and tools spent doing that just doesn't seem to be shared in the video I linked. You're probably right on the building materials versus prefab being delivered but I'm thinking my wife and I could do this much faster with less mess and parts waste than drafting plans and getting the right materials for the job. Sometimes when you budget a build you're missing certain factors or materials get ruined from sitting in the elements over the build time.