And since Dodd Frank, financing is much harder to come by. Most residential contractors who used to be able to build the same spec houses a few dozen times each

And since Dodd Frank, financing is much harder to come by. Most residential contractors who used to be able to build the same spec houses a few dozen times each, are now in a position where they largely survive off of client financing, which means even spec house plans become client dictated custom homes. It's much easier to build a dozen of something when you don't have to deal with 12 different clients/owners.