I see three options:

* he's lying, i.e. he's knowingly deceiving his audience to create hype and raise the stock price which he financially benefits from

* he's bullshitting, i.e. he's embellishing what he knows is in development with the hopes that engineering will overdeliver and meet his promises or something similarly impressive to distract from the failed expectations

* he's truthful, i.e. he's genuinely and continuously overestimating what engineering can realistically deliver and keeps being wrong over the span of a decade

I'm not sure which scenario is most flattering. Keep in mind that a lot of his claims seem to be unplanned and he doesn't believe in PR departments so most of his statements seem to be his personal judgement based on what has been reported to him. I'm inclined to believe he doesn't care much about the truth value of his claims as long as they feel like the right thing to say to him ("hashtag no filter" as the kids used to say).

I think the "he's truthful" case is the most damning because it calls his expertise in any of these fields into question. Looks an awful lot like Dunning Kruger.

He has said he is overly optimistic and believes he is truthful, and that if he didn't none of these companies would exist.

Outlier leaders are usually outliers in mindset.

But when I am optimistic but I rarely am outwardly optimistic because I know it’s lying if I am.

I think he knows that when he lies, many people take him seriously because his companies are sometimes right. Which pumps his valuation.

He has demonstrably lied about his education, lies about his family background and keeps getting caught making statements that sound plausible if you know a little about the field but nonsensical if you are an actual domain expert (e.g. nearly everything he said about software development re Twitter).

I think he's a good generalist because he (like many autistics) finds it easy to drill into domains he finds interesting and keep up with discussions at a fairly advanced level but when you do that it's important to be aware that having binged expert sources on a subject for a month straight doesn't make you an expert in the field the same way a conversational crash course over a weekend doesn't make you a fluent speaker in a new language even if you know how to order a pizza and get a general idea of what people say to you.

I've actually experienced this misattribution of expertise myself: just because I've read several Wikipedia articles and binged some video essays on a given subject I've had people assume I'm an expert when I tell them about it - except I know that my "expertise" would collapse as soon as I were to talk to an actual expert. I think this is why a lot of people suffer from imposter syndrome: because they're literally faking it by having a good generalist knowledge without realising most people in the field also lack sophisticated underpinnings.

The first two are just lying. The third is only not lying if you assume that he's extremely stupid; otherwise he would have learned by now that he's bad at estimating these sorts of things, and adjusted.