Your transient point is very appealing to me. The line of thinking that people move more-> lower incentive to build custom-> cheaper finishes/less creativity feels logical and can be tidily appended to the Enrico Moretti argument that economic opportunity has concentrated in the cities-> more people detach from their hometowns to chase opportunity.

There are two pieces of information that I struggle to integrate into this model and would be interested in how others reconcile:

1) US census data suggests (surprisingly!) that the % of residents moving each year has declined significantly since 1990, and before that was about the same back to the first data collected in the mid 40s (though with some collection gaps) [1]

2) Anecdata: most of the new builds I see around me (Boston MSA) are luxury apartment buildings or way out in the suburbs. The former aren't quaint, but are decidedly custom architecture. The latter, I stereotype as "folks settling down in the suburbs". Maybe McMansions, but I wouldn't expect transient. This one might just be a sampling error on my part.

[1]https://www.census.gov/newsroom/press-releases/2016/cb16-189...