I'm of the camp who believes it stems from motivation - for whatever reason, I've found computers (and math) fascinating and have found the motivation to spend a lot of time understanding them, without it feeling like effort. I'm not sure I'd say I picked this stuff up quickly, it's been many tens of thousands of hours.
I'm not sure I have any useful advice regarding reading, other than doing quite a bit of it (though these days a lot of it is net stuff, which is varied in quality). Lately I've been reading a whole bunch of papers on GPU, both 2D rendering and how GPU's work (the Citadel stuff is a good read). A couple years ago I read a ton of stuff on CRDT's, and while it obviously grabbed my attention at the time, I look back and kinda regret the effort spent on it.
Hope this is at least interesting, if not helpful.