If making a building involved stacking blocks then it would be pretty easy for humans to make buildings too. I don't see how these robots would be capable of installing an electrical socket, or applying caulk, or any number of important tasks. Not to say a robot couldn't accomplish these things, and maybe a quadcopter could deliver supplies in some limited circumstances, though a robotic crane could deliver things as well. One robotic crane could actually assemble the entire described structure, only with concrete blocks instead of polystyrene. It's the eclectic nature of buildings that makes them hard to build, not just piling materials into place.
