In my hometown, there is a big fight about a county regulation that requires each new residence to have its own dedicated sewer line to the city. Builders cannot build 1 line to 2 small homes right next to each other, or to duplexes, even. I believe I heard it estimated that it adds $10k to the building cost. This interference in the market pushes the margins and it artificially makes more sense for builders facing that new fixed cost to build bigger homes for better ROI. So basically all the modest-sized housing (let's say 1k - 2k sq feet) comes in the form of older homes, and new homes are 2,500+ sq feet.
It's a college town but it's a college you never heard of and there is no reason for real estate to be expensive there. There are lots of young families and very few can afford to buy. It's kept the landlord's in good shape, though.
You're not wrong about your points, but what I'm saying is we've (all generations) definitely messed up the housing market. That small market was not demanding bigger housing.
Most things get cheaper over time. Wages increase relative to most products in the long run. Excluding the price of the land, housing should be cheaper to build per sq foot today than it was in the past. I don't think it is, even if you didn't use fancy appliances or fixtures. It's an interesting question.