Tesla reportedly fired Omead Afshar, its head of North American and European operations, in June following a massive drop in European EV deliveries. Afshar, who joined Tesla in 2017, was just promoted to the position in November. The Wall Street Journal described Afshar as one of Musk's closest confidants at the company.

"Musk is CEO -- the buck stops with him. As a CEO in a competitive environment, he's the one who has to have the vision and lead the troops," David Meier, a senior investment analyst at The Motley Fool, told ABC News. "But there's a lot going on in the world that impacts Tesla's business."

Nelson downgraded the company’s stock to a neutral rating in April. But even some of the Tesla bulls on Wall Street are saying that the time for Musk to take action is running out.