Not necessarily. Other peoples' work can assume what "everyone knows"; starting from first principles can (sometimes) show up where that's the case. That doesn't mean you're not very smart; it means you're aware enough to know that some limitations that aren't real creep in to the body of knowledge of a field.
Or it can be just arrogance. (In fact, even when it's reasonable, it probably also contains some arrogance...)
I am in agreement with you. The OP is overstated. I have heard Musk interviewed a few times. When asked to explain more about his phase "first principles", he usually talks about (paraphrase) "delete as many things as possible". It is an interesting way to think about project planning. At a bare minimum, he has created several incredibly successful businesses in his lifetime, so he must be doing something right.
> At a bare minimum, he has created several incredibly successful businesses in his lifetime, so he must be doing something right.
No, this is a common fallacy.
The main reason to get crazy rich and successful is statistics: be lucky. I.e., accidentally do the successful things. And usually starting rich helps, so you have the opportunities.
Crazy success is not a measure for capability. There is no correlation. Yes, it is sad, so despite this, the fallacy is a great motivation for many.
Or it can be just arrogance. (In fact, even when it's reasonable, it probably also contains some arrogance...)