Contractors can't think of everything, I used to build houses {when the economy used to warrant it} and you have the bank saying "we need to close in 130 days" the home owner asking stuff like "can you do an asphalt driveway for the same price as gravel", the subs saying "monday when they mean Friday night}, the inspectors interpreting code like a 3rd grader would, and by the end of the build if you didn't strangle someone you may make a months pay for 4 months of work....
What I did do and it took a while to learn was made a list of stuff for the new home owner to look over and consider, that other owners had as after thoughts, a lot of it was electrical and wiring like full house audio, sill plugs {for window lights, I hated not including them when we built colonial style homes, but some people wouldn't want them, they would pay extra for the inner window frames, but not get the lights}, a generator outlet, 3 wire to the ceiling lights {for fan control}, central vac, ect, there was a lot of plumbing stuff to, like adding radiant tubing to the garages and basement floors that looked like someone would want to finish, its cheap at .28 before the cement is poured, but after its impossible... Some people would think ahead and others would think bottom line...
My point is it may not have been the builder, it may have been the original home owner. I do hvac all the time and tell people, look its an extra $900 to run the metal down the side wall of the basement and you will save all the headroom, and you would get sick at the amount of people that dont care, nope, run it as cheap as possible, the next owner can worry about headroom, or the customers that spend all this money on an inground pool and don't at least run the gas line and electric for the heater while the ground is torn up, its $200 in materials to do it now, or impossible to do it later, you choose?
OK my rant is over, sorry...
Trix, I see what you are saying about the wires, still a cool picture...