Per the rules of this forum, magic is ASB.Or use magic. As Terry Pratchett did with Going Postal, when B.S. "Bloody Stupid" Johnson used "New Pi" to build a mail sorting machine. Caused all sorts of problems when the postmen found themselves delivering letters BEFORE they had been written.
No, I don't think I miss your point at all. Yes, the author can write whatever he wants. But you might be missing mine. By the rules of this forum, stories that ignore/break the laws of reality go in the ASB sub-forum. ASB is not exclusively 'intervention by omnipotent beings'. P-M has chosen to write in the After-1900 sub-forum, so therefor he's pretty obligated to continue to abide by the laws of physics as we perceive them.You miss my point... in an Alternate Universe story, created in the mind of a tale-weaver, the laws of our Universe mean nothing!! The "natural laws" are completely dependent on which of the Multiverses s/he is weaving a tale about.
You bring up ASB. As an explanation of a story taking an unusual track, ASB can work. Take, for instance, S. M. Stirling's Emberverse series. In Dies the Fire, Something happens that causes all high-energy 'things' to no longer work. The Change. After which, things aren't the same; gunpowder no longer goes "Whoosh!!" when lit on fire so firearms no longer go "bang"; nuclear, internal combustion & steam engines cease operation; electricity in batteries, generators, etc., no longer work. But life-forms continue to function; nerves still pass electrochemical messages; brains still think. I won't spoil the story, but at an early point, many people adopt an attitude about the Change - ASB caused it, curse Them!! The cause is revealed at a point in the series (ASB are in the running), but I'm not gonna throw out spoilers in case someone here wants to read more excellent alternate history stories.