Steve is an outlier, there is absolutely no doubt about it. There also can't be doubt that Steve did have a few strokes of luck that landed him at the right place in the right time, but I think you are also right in that the evidence of his skills are found in the fact that he was consistently successful.

I think being consistently successful in your ventures is a sign of true skill more so then being wildly successful, and it's safe to say that consistent success comes from experience or talent (if you are lucky).

EDIT: Technical talent is always important in a company that is based in technology. Steve's ability to design complemented the technical talents of the people he surrounded himself with, he knew that design and engineering are a nearly perfect couple with the right balance.