House size must also play a factor. I did a quick search and it appears to play a major factor and house sizes have gone up massively. Takes longer, more materi

House size must also play a factor. I did a quick search and it appears to play a major factor and house sizes have gone up massively. Takes longer, more material, more people to build those McMansions with all the crazy gables. Prefab houses can go up pretty quickly but they don't seem that popular. If they were more popular then maybe they'd gain a scale that would make them a much cheaper option.