It's interesting how this goes in cycles. Car companies used to be integrated. VW had a factory where they poured melts in one end and pooped out completed cars at the other. The trouble is that sort of vast and sprawling enterprise breeds inefficiencies. The response to that was to start outsourcing more and more work and lean on their suppliers for innovation. Then they suddenly find they can't differentiate themselves in the market and start bring things back in-house again. VW are bringing software development back in house now because it is a key part of the product.

Plus ça change, plus c'est la même chose.

I guess the key is figuring out what's best done in-house and what works best farming out to suppliers. SpaceX found it cheaper to do many things themselves than go out to the established aerospace suppliers. Whether that remains the case ten years from now is open to question.

I wouldn't be surprised if aerospace suppliers got rather fat and lazy sucking on the NASA and DoD teats.

This might be a mistake though. There's a reason all car makers moved to a heavily subcontracted, complex supply chain.