I expect that if Ayn Rand were actually pressed on the issue of "do the successful owe at least part of their success to their upbringing" she'd be forced to admit that yes, they do.
Peter Keating (the shadow or antagonist of Howard Roark in the Fountainhead, with comparable ability but different choices) provides a counter-example: he loves painting, but doesn't practice it until after many years of ("aw, hell") architecture. When he eventually does turn to it, Howard Roark gently tells him "it's too late".
Yes, her heroes' ability (brilliance) and loves (values) are already in place - but in this, they are no more gifted than anyone else. What differentiates them is their consistent choice to apply their ability to what they love, seek mentors, etc. As a personal choice, it is within their power, and does not come from their upbringing. It comes from them - as do your choices (of course, they also have many blessings and opportunities - as do you).
Steve Jobs was not and is not a huge computer hacker. Not like Bill Gates. But still, he was able to conceive of the idea of a personal computer, before anybody else had the idea. How did he get 10,000 hours working into that? From his own words, he got the idea by dropping acid and deciding that people weren't using this new technology in a way that could change the world. He repeated this again and again with the iPod, the iTunes store, the iPhone, even with how he changed Pixar.
Jobs is unquestionably talented. However, it isn't shown that he's talented solely because he practiced at what he did heavily. I think that part of what makes Jobs as great as he is is his unbridled ego, his belief that he alone is right until proven otherwise. And that's something that you can't entirely pin on the society around you.
One of his abilities, absolutely, is the ability to spot which people are incredible at what they do, and to put them in a situation in which they can do it. In Pixar, he created the central hub that got people interacting with one another. (I forget the article that talks about this - anybody have the link?) He has a genius ability to fix things, to make them better.
I argued once that if Jobs hadn't found Woz, he'd have found somebody else capable of doing what he needed done. And I think the end result would be largely the same. Woz was a programmer. Jobs was the visionary and the designer.
I agree that not everybody can "remove everything but the essentials" - but I think that everybody can try to do it; can practice it. The difficulty is in knowing what the essentials are, which requires knowing what you are really doing, and what it needs. Through practice, we improve.
Could it be as simple as believing in your intuition? I mean: to consider what you believe is essential, and then act on it And find out if you were right or not. Then repeat many times. Without loss of enthusiasm...
It's likely that Jobs saw this early on.
EDIT I see now you were part of the sockpuppet trolling rampage. Now defeated and deleted: http://news.ycombinator.com/item?id=360128
Ayn Rand says no; Gladwell says yes.