I've watched Notch program, and while he knows of lots of game related algos that I don't, he's not a magical snowflake and it'd take me no time at all to find those algos and implement them. There are huge swathes of the code he writes that I'd be comfortable writing at about the same speed.
From experience solving other complex problems in unrelated domains, it might take me 2 or 3 hours of googling, once, for particular problems. The worst ones a day or two. After I've done it once, it's not hard to either remember or find that code and remind myself.
It certainly wouldn't take me 1000s of hours as you seem to think it would.
I don't believe in 10x programmers. I don't agree with many things stated in this article.
What I believe is that most programmers have a complexity ceiling, where if the code goes past a certain level of complexity they are practically useless on that code base. Often they can just deal with bits of it, but try getting them to do a large scale change and they simply can't. They can't reason coherently about their changes. I think both natural talent and experience raises that ceiling, as does time spent on a particular code base (just for that code base).
And that's where I think the 10x myth comes from.
EDIT: I've even seen projects where the original authors couldn't make much more progress with an operational product, I call it 'coding themself into a corner'. They took the project past the point of the complexity that they could personally handle.