But… he literally isn't. Like just look at twitter, he has ruined it from day one with bad decisions day after day whose impacts haven't shown directly, but now appear more and more with embarrassing effects (The verification badge which is now worthless and has been used to impersonate people and cooperations, the two factor authentification which stopped working, the self-DDOSing, the maximum amounts of tweets one could view per day, the old tweets that got deleted due to a glitch, etc.)
And in other companies it's mostly other people managing the stuff and cleaning up the mess he leaves; especially SpaceX is currently just glad that he isn't too busy with his X playtoy to bother them.
The only thing you may call him somewhat successful in is making out companies that have a potential so he could get into them early and claim their success.

Being a succsessful businessman does not make one a good businessman. Half of the equation is ethics, because it fucking matters.

A successful businessman with bad ethics and an unsuccsessful one with good ethics are both bad businessmen.

The only good businessman is one who both succeeds and has good ethics.

While he has had some success, he's also demonstrably been a glory hog benefiting from crazy good luck.

He had an Internet company during the first dot com boom. He got a bunch of cash from Compaq for effectively nothing, because businesses had to snap up anything vaguely Internet. Right place at right time, basically won a lottery.

So then he founded an Internet bank. But want allowed to lead it, no matter, either way it was overshadowed by PayPal, which was a runaway success. Somehow he managed a merger with him being put in charge of the joint company. Then he almost tanked it and was put aside to salvage the company. However, he managed to be popularly thought of as "the PayPal guy"

He founded SpaceX. Off the top of my head, that one seems fair enough.

Then you have Tesla, which existed prior to him Knowing about it, yet he still insisted on being called a founder. It's possible that without him, Tesla wouldn't have gone far, but either way, he's been a glory hog about it to the point of again getting himself framed as "the" Tesla guy.