CEOs generally have to do work to make sure that everyone else is executing well and toward the right goals. Successful CEOs either need to be hands-on and skillful, or get lucky with subordinates who execute well and toward the right goals themselves. Elon's a mix of those to the degree he's successful, like any.
The work is maintaining trust from the board such that they continue to give you the keys to the kingdom. It may not be time consuming work, but still work most people are unable to do.