Just for one specific example: even if I was in his exact situation back then, I wouldn't mortgage out my house, ask friends and family for loans, cash out all of my savings, and then dump it all into my failing green energy startup during its "make it or break it moment". But he did, and none of what Tesla/SpaceX are presently would have been possible if he didn't make that decision.

And that's just one extreme thing that he did that I know for a fact I wouldn't have been able to do, even with the resources and everything else he had.

What's so unlikely to you about the idea that he's relatively intelligent and that's played a part in his success?

People want to pretend it's all luck and connections. I don't think it is, and I think people pretend that to make themselves feel like they could have done it if only they had the same resources.

Nothing, I haven't even questioned his intelligence or said anything about him at all.

I just don't have a slightest clue in how to assess his intelligence and compare it to mine based on what I know about him, which makes me wonder what's making it so obvious to you. Especially when talking about things so blurry as "business decisions", since there are so many outside factors at play in any business that one's intelligence is never a single thing that determines business success.

Occam’s Razor. Maybe it’s possible it’s all sheer luck? But most likely - he’s a shrewd and intelligent business man.