The best firearms oils actually have very little to do with actual load much to your point. The largest issue to pull off successfully is corrosion prevention with the thinnest of oil film on the weapon. The corrosion inhibitors needed to pull off reliable performance successfully are different than those in an engine oil or transmission fluid where you have copious amounts of oil being slung around. The detergents present in motor oils also being hydroscopic don’t necessarily help. The mil spec on wear is very loose. The threshold for salt fog corrosion is 100 hours. I have not personally seen results to back up my feeling but I would be skeptical that a motor oil or transmission fluid would pass a 100 hour salt fog. That being said most people don’t use their weapons in the environment that the military does which would explain why people get by with the expansive list of less than ideal gun oils. For me, I really care about my guns. Having the lab and raw materials available to make good choices we made a gun oil that wears a fraction of the mil spec and we ended up terminating the salt fog test at 500 hours with a 100 percent percent perfect result. Most people formulate just to pass so I am comfortable with that margin. Guns stored in a safe have an easy life. The harder the service the more important the right gun oil is. Fortunately there are a lot of good ones out there.
Wpod, great choice on 1911. They are my favorite!