It's been clear for a while that Musk has had these sorts of issues. There's the infamous pedo guy incident stemming from Musk's unwanted attempts to help in the Thai cave rescue. Before then, there were quite a few reports during the early ramp up for Tesla Model 3 about several of Musk's bad ideas re car production. There were also several reports that SpaceX was only as successful as it was because it had a COO who could insulate the company from Musk's antics.
So it's been clear for at least a half dozen years or so that a successful Musk company needs a team to manage Musk and keep him from unnecessary interference in the company, but it may have required paying more attention to what he did. What changed when he bought Twitter is that he is now articulating a vision that is far less comfortable for many people ("stop banning fascists" is rather less inspiring than "I want to live on Mars"), and also, many of the failures of his micromanagement are far more visible to the general public on a large social media platform than a low-volume rocket or (at the time) auto manufacturer.
So it's been clear for at least a half dozen years or so that a successful Musk company needs a team to manage Musk and keep him from unnecessary interference in the company, but it may have required paying more attention to what he did. What changed when he bought Twitter is that he is now articulating a vision that is far less comfortable for many people ("stop banning fascists" is rather less inspiring than "I want to live on Mars"), and also, many of the failures of his micromanagement are far more visible to the general public on a large social media platform than a low-volume rocket or (at the time) auto manufacturer.