SpaceX hired Gwynne Shotwell shortly after being founded, and she has been COO/President the entire time. While Elon may be the face of SpaceX like most of his companies, and may be responsible for major goals, he hasn’t really been in the driver seat, letting Gwynne handle operations.
It seems clear that this is the difference between SpaceX and his other ventures like Tesla and Twitter where he has been directly making changes to daily operations. Even with a separate CEO at Twitter, it’s clear he’s still making daily operating decisions.
Elon sucks at operating a business directly, he needs someone else to actually handle daily operations, to filter his thoughts and decisions for how realistic they are to implement.