This is nothing new - Tesla has a long history of high-level people leaving the company. The closer an employee is to the top (Elon) whether organizationally or functionally, the more at risk they are. Like many great company leaders, Elon is very demanding and has a firm belief in his own concepts. If, as an employee, you differ with Elon, you must have incontrovertible proof that you are correct or you will find yourself leaving the company - either being asked to leave or put in a nearly impossible work situation. And this isn't necessarily a bad thing for a fast moving technology company like Tesla. Apple (Steve Jobs) and Oracle (Larry Ellison) are two examples of technology companies with brash and demanding CEOs.