More fundamentally, there were contracts. SpaceX does things itself; there's no legal friction internally. This gets back to the "Theory of the Firm" for why

More fundamentally, there were contracts. SpaceX does things itself; there's no legal friction internally. This gets back to the "Theory of the Firm" for why firms exist in the first place (transaction costs). The need to codify what work is to be done in contacts is antithetical to SpaceX's rapid development processes. https://en.wikipedia.org/wiki/Theory_of_the_firm https://en.wikipedia.org/wiki/Theory_of_the_firm