It's fascinating how nobody was making this claim of a non-technical Musk up until the moment he stopped being loyal to one particular wing of US politics. Now we see a concerted effort to diminish his achievements. Do you people really think this will work? There is endless testimony from people - independent of Musk and in the space industry - saying that the dude is an honest to god rocket scientist who single-handedly made SpaceX happen through sheer force of will, engineering ability and personal investment. He routinely displays a fluent understanding of orbital mechanics well beyond what any normal CEO would be expected to display. Anyone can read his bio or the testimony of people who work in the space industry and understand that Musk was (and still is) intimately involved in every aspect of SpaceX, down to detailed engineering decisions.
Shotwell meanwhile is regularly described as managing the business development side. She negotiates with customers and oversees day to day operations. This is critical work that she clearly does very well, and she has an engineering background. But I can't find examples of people claiming that she drives product development or overall strategy for SpaceX.