I think you have to add forestry to to the costs. Lumber tree cultivars grow at fairly predictable rates and varying the dimensions of the finished lumber would mean either much reduced yield or delayed harvesting - more costs per board foot, either way. And then the trucks that transport the logs would have to be modified, and/or loads decreased, sawmill kilns and timber yard storage racks modified...

Ramifications ripple everywhere in an efficient ("optimised") system.