Unless they accomplished a miracle by building a world-class engineering team from zero, there must have been a catalyst.
Just a couple examples would include Tom Mueller, who was responsible for most of the design of the propulsion systems SpaceX currently uses (including the Merlin and Draco engines), and Gwynne Shotwell, SpaceX's President and COO. SpaceX absolutely owes its existence to Shotwell, both its commercial success, and the fact that it didn't die (a number of times) are directly due to her.
From an outsider's perspective (_very_ outside), it seems like it's really the "synergy" of Elon and Gwynne that have made SpaceX what it is today.
There is - having visionary, charismatic founder(s). This pattern has been successful at Apple, Microsoft, Amazon, Facebook, Netflix, Tesla\SpaceX, Google.
That isn't to say they haven't been doing interesting things from a technical perspective (they're landing rockets on barges, after all), but the real secret to their success has been taking proven technology and doing it better/more efficiently (for instance, the fundamental design of their rocket engine, the Merlin, dates back to 50's).