I agree but this point is orthogonal to the main point. Plumbers and electricians build to code in an environment where physical reality remains constant and they operate on expected inputs. A civil engineer is not held to account for a failure if gravity suddenly reverses itself. If I shock a circuit board with static electricity and it fails is that an electrical engineer's fault? If I put 20,000 psi through a household plumbing system and it fails is it the plumber's fault? These designs are only expected to operate in a narrow range on a small number of expected inputs / variables and that is easier.
Software can basically expect infinite permutations of inputs at any time and is expected to give good outputs and no bugs 100% of the time?