It was illustrating narcissistic personality disorder. Debating whether or not Musk delivers, or what personality traits might be behind delivering or not, is irrelevant to whether or not Musk illustrates NPD. It is easy to find examples of his behavior that matches [a layman's understanding of] NPD, so it seems fair.
Saying that Musk's personality resembles NPD doesn't say whether he is or is not effective at some tasks.
It has nothing to do with the rest of generally good article. It's just a forced personal stab at disliked public figure. Ironically quite the opposite of egoless. Your politics are a big chunk of your ego. If you can't leave them aside and when dealing with technical stuff, then it's very much egocentric. Which surprise surprise is typically the case.
Saying that Musk's personality resembles NPD doesn't say whether he is or is not effective at some tasks.