I can understand wanting to avoid the extremely invasive traditional measures by seeking a lower impact solution first, but it's hard to see how someone with more money than God could get caught with his pants down by the progression of his disease.

Reading between the lines, my impression of the story (as given by 'google', but at least integrated over a few sources) is that his disease was typically slow-developing and it was expected there was some time. Jobs wanted to try the "diet approach". (There is a lot of information out there about links between diet and cancer; I don't know what to make of it but it's not pseudoscience, just highly 'organic' and non-linear). I have a strong sense that Job's plan was to try the non-invasive/wholistic approach until the cancer progressed. Perhaps he even felt like he was brave -- he wasn't rushing to have surgery but had the mind-over-fear frame of mind to explore alternative options. In parallel cases, it is sometimes overly dramatic to remove organs for fear of relapse when other treatments are nearly as effective. Consistent with this hypothesis, Jobs had the surgery as soon as it was determined the cancer was growing rather than shrinking It was still a textbook case -- got cancer, had surgery, now in remission, and Jobs gave a thank-goodness-that's-over speech.

However, unfortunately, in the end the cancer was growing even more aggressively than anticipated. Perhaps a cancer doctor can tell us what portion of the bell curve Job's cancer would be found in, that it was more aggressive than expected. If Job's approach would have 'won' most times according to his own utility function (given a random cancer, by selecting non-invasive approaches over surgery) then he could be more rational than appears in this particular Everett branch.

My motivation here is that I tend to credit consistently successful people with being rational, or at least good at winning, even if their methods seem strange or there is an element of gambling to their successes.

(I was downvoted just a point so far -- I hope to hear the reason for the disagreement, I suspect it is with my philosophy rather than with my assigned probabilities.)