Having worked at Apple for a large chunk of the last decade, I'm not sure that Steve Jobs is necessarily all that integral to their continued success. Certainly, Apple will never be without Steve what they can be with him, but my interactions with Tim Cook, Ron Johnson, and a handful of others lead me to think Apple will be in very good hands once Steve's out of the picture. Apple-without-Steve will very likely still be head-and-shoulders above everyone else in the industry.
I blogged about my experiences both in Apple Retail, and in "corporate" Apple for a number of years. Eventually I took it all down, though not due to any pressure from the company. I took it down because I was inundated with emails from 15 year olds who wanted to know how to get a job in an AppleStore. But I worked for Apple for 6 years in Retail and AppleCare, and interfaced extensively with hardware engineering. I'm not sure I'd have anything interesting to say, but if you have any questions, I'll try my best to answer them.
I was working for AppleCare at the time this was written. AppleCare management saw a huge uptick in calls from customers curious about how to carry such an (at the time) odd form-factor and insisted we have a kbase article for it.
It's not about one man. It's about the culture.