We want to believe in the cool, if a bit unhinged, hero-engineer that builds all the cool stuff we were promised in all the sci-fi movies as kids but failed to materialize, such as Mars colonies and self-driving cars. A lot of that failure is due to some things being a ton harder in reality than fiction, but a lot is also due to a managerialist, short-term culture that no longer seems to be thinking big and taking risks. Musk is the avatar for those who want these cool things and kicks back against the prevailing culture - a real-life counterpart to the billionaire genius in the Marvel movies.
The problem is, of course, that Tony Stark is a fictional character and Musk is not. Not only has he been drinking his own kool aid of late, but he's not much of a hero either, rather a spoiled bully who punches down.