I disagree with Hubka’s rejection of the McMansion as a topic of vernacular study, but I agree that it is not quite vernacular, either. However, I think there are some things about the McMansion that can only be understood through a more vernacular framework, such as their ubiquity and the means by which they are built. McMansions are not usually designed by architects but by builders, most of them massive corporations like Toll Brothers, Pulte Homes, and Ryan Homes that traffic exclusively in master-planned tract communities. Like most vernacular architecture, the McMansion might best be considered a typology—an architectural configuration that adapts over time but remains generally stable.
If you kidnap an architect and force them to design a building and keep adding requirements like people do to the builders, you'll end up with something very McMansion-like.
A good architect will try to convince you that what you say you want is not actually what you want, but they'll eventually quit or acquiesce.
(Some of the best "super large houses" are the ones that have other design limitations, such as some of the log homes you see.)
