3 ideas
Unlike manufacturing, construction productivity has stagnated because buildings are large, site-built, and customized, preventing the centralized factory conditions that allow specialization and automation. The product is too big to move to the machine, so the machines and labor must come to the product each time, defeating economies of scale.
Prefabricated and modular construction repeatedly fails to displace conventional building because the savings from factory production are eaten up by transportation costs, site assembly, and the loss of flexibility to adapt to site-specific conditions. The fixed cost of a factory also requires steady high volume, which fragmented and cyclical construction demand cannot reliably supply.
Every building component must simultaneously satisfy structural loads, weather resistance, thermal performance, fire safety, and cost, so design is the negotiation of trade-offs rather than the optimization of any single property. Viewing a wall or roof as a stack of conflicting requirements explains why seemingly simple improvements ripple into unexpected failures elsewhere in the system.