For what it’s worth, NASA doesn’t directly build much. Even the Apollo program was a huge web of private vendors (many who still exist today).

SpaceX is/was just another entry on the long list of private contractors commissioned to build things for NASA, DoD, et al. But different here is that SpaceX worked at very very different speed than Aerojet Rocketdyne, ULA, and all the other old-space fossils. Still, those old contractors are valuable for other things — good welders, technicians, and engineers take many years to train and these old legacy corps provide a steady income stream to maintain a certain level of manufacturing readiness.