Just like how you say the work engineers do is not magic. That literally 1000s of other people can do it.

That's also true of marketing, sales, and product development.

Takes sales for instance, sales is knowing your clients needs, and knowing how your product fits into those needs and then having a shit load of conversations about how your product fits clients needs. There isn't any magic. You can contact more people, and you can convince a few percent more people to buy your product.