A 4x8 sheet of 1/2" Gypsum board weighs nearly 60 pounds. A five gallon bucket of paint weighs about the same. A quadrotor couldn't finish an office because it would be too large to fit through the door...never mind the rotating blades.
You're right. But. As robotics becomes practical for building, we will not just replace human with robots. We will change how we build to make it easier to build with robots.
For instance, I was noticing that while you might not want to use magnets for everything in your building, you could use them as a guide during that intermediate period where the robot can't just put things together, but they can be mostly correct. Magnets could be used to do things like guide pieces of wood together with a sheath containing powerful magnets, then the wood can screwed together, then the sheaths recovered and used again on some other bits of wood.
The biggest challenge may very well be keeping codes up to date. I suspect that the crossover may very well be swift when it happens; robots are improving very rapidly and when they cross the line where they are a more cost-effective way to build a house, they aren't going to sort of edge up to it and pull alongside it, they're going to blow right past it and keep going.
Times are tough now but the next several decades still stand to be very interesting times, in all senses of the phrase.
(Oh, and personally I don't think flying robots have much future in construction. The economics are nonsense, excepting cargo helicopters, which are regularly used for some purposes today. I'm more speaking in general.)
It's funny, people have been talking about prefab houses (related, but not the same, as on-site robotic assembly) for years, but they still are a niche item. Despite all kinds of efforts to popularize them, such as:
I suspect that protectionism will delay the "robot revolution" long past the time when it's technologically feasible. Building codes will be changed in some way to require human labor, building material suppliers will be pressured to "run out of" the parts needed by robot builders, etc. It's been my experience that few people outside of tech actually like the idea of robots doing anything that a human could do.
