There is a phase in every company when that is a crucial thing to have, the earlier in a companies life cycle the more important it is. And then comes the point where such deep involvement of the CEO / founder is less important and even turns into a liability at one point.
At least for Tesla, I have the impression that this is, indeed, becoming a liability at the moment.
When the very top has a measurable impact on low level discisions it is a) eating up attention from the top level b) delaying even small decisions waiting for top level involvement and c) carrying the risk of bad decisions as the top level is, by definition, missing the detailed knowledge necessary for the majority of low level decisions. Not even to speak what that does to innovation and the flow of ideas and corporate culture in the long run.
Other famous examples of where this can end are VW and, at a smaller seriousness level, Bezo's deep involvement with the Fire phone.
Automotive mass production is, from a certain perspective, more complex than launching stuff to space. It is also a very well understood domain, first and foremost from established car manufacturers. So it would have made sense to also memorize some books covering that topic and than getting experts onboard. It doesn't help that an EV is less complex to build compared to traditional cars, so in that regard traditional manufacturers actually do have an advantage. I don't remember when he said it exactly (I think around the time Tesla bought this German manufacturing equipment supplier), but Musk stating that he also wants to revolutionize the way cars are manufactured. Why would you do that when your primary goal, one you are on very good track to accomplish, is revolutionizing mobility?