I think you're making some good points - Zip2 and X, whatever the ultimate "quality" of the tech / UI*, realizing the opportunities, pushing to ship quickly, etc., that was all key. Musk was a clear driver.
With SpaceX and Tesla, I'm not as sure about the facts - I believe there is / was a strong component of "Jobs", but also (especially at Tesla), plenty of pissing engineers off with really BAD proposed solutions. I.e., plenty of "thinking differently" (which can be very valuable, and Musk has had some notable successes here and there), but not enough "filter".
I would say, though, that as his value** has fluctuated on the technical side (and, I personally have the sense has likely never been that high), he did build some real strength in "branding" and selling / marketing. He created / built a personal brand, especially, that was quite important in raising money / funding for R&D etc. at SpaceX and Tesla, especially.
Ultimately, his arc is ... an archetype. His arc is a great example of a pattern that is seen frequently (enough) among ambitious people who become very successful through drive, risk-taking / (some degree of) unconventional thinking, etc. You see this with people like George Lucas, and part of it is the "yes men" trope alluded to in another comment.
Basically, early in their careers, their impulses and "visions" and the like are tempered by others and organizational structures of various types. This tempering is a key additional filter which helps keep their creativity and problem-solving skills etc. more focused / ~"pointed in the right direction". But, over time, they gain more and more power - more and more freedom to do what they want, to not have to listen to anyone else. The decline in quality / success / etc. of their projects and companies seems to very closely mirror the degree to which they are unfiltered / unconstrained / no longer (so) dependent on others.
Basically, classic human "ego stories" (that don't necessarily depend on "big ego", but even the simple blindness of "ego" we all have) recognized and well-explored by the Ancient Greeks, in particular (e.g., "Icarus", "Odysseus", etc.).
* Not really pertinent / germane to this discussion
** To the degree I have any ability to judge, particularly as regards actual knowledge of much of this history (similar to the vast majority of people)