Musk is currently the CEO of three different companies: SpaceX, Tesla, and, of course, Twitter.
But like many CEOs, he's accumulated a huge fortune by juggling several companies and directorships at once.
While Musk may be an extreme case, he's also the perfect example of the modern CEO: a chaotic blend of unproductive micromanagement and highly-paid absenteeism.
In the extreme, some CEOs like Musk have taken on the management of multiple large companies.
And Musk isn't the only executive who would be better served focusing on one task.