Transportation is by nature highly distributed among a wide range of actors, unlike industries like semiconductors where the costs are centralized in a factory where a single agent can optimize everything.
In other words, the majority of improving construction costs is actually a political problem, and engineers are unsuited to optimizing it. Transportation costs can be reduced, but only at a collective, national or state-wide level. Moving vast quantities of lumber, insulation, wiring, drywall, roofing and other housing materials across state lines is much more a political coordination problem than an engineering one. Sure, a team of engineers could design a more efficient, cost effective transportation method - but how would consensus ever be achieved to actually build the thing and align all the disparate interest groups to rally around it rather than opposing it?
My hot take is that in the current era (at least in the United States) "Smart" people have neglected political concerns in favor of technical concerns. But the risks aren't technical, they are political, so this is inefficient. The problem will not be solved simply by engineering, no matter how clever the engineers are, if they are limited to purely technical approaches.