I was glad to discover this is an analogy to electrical circuits further down the page. It's a good topic to understand, the write-up is comprehensive.
> They are the only man-made technology in history that we don’t fully understand from first principles
…what? What about bicycles? Ice skates? General anesthetics? I feel like there are a ton of commonly-used man-made items we don’t fully understand from a first-principles perspective.
No, I don't think you are missing anything. Only recently have engineers been inventing things from "first principles". I think for the majority of human civilization we've mostly invented and improved through trial and error.