Musk Inc. is, in essence, a privet equity company. He raises a fund, and invests it along with his own cash into a business he knows well, and with which he believes he can disrupt the status quo.
He's very hands on, understanding all the important core details, setting culture, and pushing hard. But he also delegates to experts he brings in to run his businesses.
It's obviously not the same as PE, but there are distinct similarities. With each of his companies he clearly can't take an active role all the time, but what his team are experts at is identifying the areas he needs to be on top of, and they will quite literally fly him in for it. It seems to me it's always the start of something, be it a new company or project. He will be there 24/7 getting it off the ground, but then hand over to lieutenants to run.
It's a formula that seems to work again and again. We're (well those of you in the US) are in for an interesting time over the coming year as he has a new project to kick start.