Who else is creating exciting companies such as Tesla, OpenAI, Neuralink, and SpaceX? I can't think of anyone else who has started such exciting companies. No need for a PR firm at that point.
You know of those four (and can't think of anyone else!) because Elon Musk sold his vision to investors, employees, and the public through impressive salesmanship and an obscene amount of both grit and persistence. He aggregated resources and did what you do when you accumulate wealth for business purposes; he spent it to forward his goals. Some of which went towards impressive PR stunts and people wrangling.
Musk gets such great PR because the stuff he's done is actually an order of magnitude more impressing than others who have done "similar" things.
It's pretty analogous to people saying Steve Jobs had "amazing PR". It's easy to have amazing PR when you have amazing products, and so many of Apple's products (the Mac, iMac, iPod, iPhone, iPad) really were game changers in terms of functionality and usability.
The thing is; the entire point of his PR, no matter who helps perpetuate it, is built to craft the very opinion you have: Elon is amazing, and he can do it all on his own. While that's probably true to a large extent, it's not the only "truth" and reality. I, personally, am interested in the stories of the people who have helped him along the way - however few or many there may be.
Paypal was not even built by Elon Musk...By the way.
Again, it's similar to the argument some people make that the iPod was just another MP3 player, or the iPhone was just another phone.