When I first entered the working world as a programmer and administrator of an "academic computing center", in the early 70s, you met men like Ray - ex-military, GI-bill educated, learned computers from the electricity on up in their mid-career, rather frequently, either as customer engineers for one of the big mainframe manufacturers (there were 7 or 8, depending on when and how you counted), or from the minicompute…
Computers based on integrated circuits were more recent. But the foundations were much older.
For example take the punchcard. Punchcards as a way to work with automatic computing devices go back to Hollerith machines and the 1890 census. That was how IBM got started. The phrase "Super Computing machine" dates back to 1931, and referred to a tabulating machine built for Columbia University. Raytheon was producing and selling analog computers starting in the late 1920s. Much of the calculations for the Manhattan project were done by machines - Feynman talks about this in Surely You Must Be Joking, Mr. Feynman.
And to give a sense of how much history there is, one of my favorite essays in the 1945 essay, As We May Think, which you can find at https://www.theatlantic.com/magazine/archive/1945/07/as-we-m.... It provided the inspiration for both hypertext and the science citation index. The recombining of those ideas in the PageRank patent was the foundation of Google. But how could someone in 1945 understand computing that well? It is simple! Its author was the man who designed those computers Raytheon sold in the 1920s, and among other things was in charge of the development of mechanical computers for the Manhattan Project. (OK, he did a lot more than that...)