They didn’t say anything about efficiency. It’s all cost driven. Cheapest inputs possible. The PE backed builder isn’t dealing with the building in 2 years, what do they care how well it works?
If you just look at hard costs and ignore beauty and comfort, is it also the cost-over-what-timeframe question? If a building is expected to be actively used for 100 years vs 20, you get to different decisions.
My other question that I've never found a good answer to, is with mechanization, how is it that "cheap" modern buildings are so expensive. Or were old, traditional buildings super expensive? What is the cost of a unit of beauty per year, then and now...?
I think most developers have a captive market. They don't really compete, they build whatever they want, and still sell, because somebody somewhere will still buy, since they know they can sell for more.