More generally, SpaceX doesn't have to pay the cost of crossing organizational boundaries. When that happens, unless the parts are standardized and commoditized, then requirements have to be formalized, contracts and costs negotiated. Time and again SpaceX found it was cheaper and faster to just do things themselves rather than buy from traditional aerospace contractors.

"It also hasn't had its funding turned off and on."

That one's a killer. I was once a project manager at an aerospace company developing a new processor chipset for space applications. Our government customer would run out of money near the end of every fiscal year, forcing us to shut down. Then a few months later they would secure funds and ask us to restart. By then most of my staff would have been reassigned to other projects. It was stupidly inefficient and caused costs to balloon.