If the toilets at all those firms started operating in reverse, very little would get built. The conclusion is that plumbers are extremely important, not that plumbing is de facto engineering.
IMO what we really need in software is something like the various codes which govern fire safety, efficiency, etc of modern buildings. It exists in some safety critical domains but should be more widely applied.
The safety codes are where we accumulate the hard-won knowledge over time. Many of the rules in the codes were paid for with human lives lost.
[0] https://en.wikipedia.org/wiki/International_Code_Council