Not a very edifying or dignified question, but I'm curious: do they spend every waking hour on ELU, painstakingly earning 10 points here and 15 points there? Or do they just strike lucky with an answer which brings them thousands of points?
Very few high reputations at EL&U are built on what amount to slot-machine jackpots. Indeed, the 200-point daily limit for reputation is designed to prevent someone from gaining many hundreds of points from a single answer in a brief period of time. A timely, well-received answer may pile up 40 or 50 upvotes in a day, but only the first 20 of those votes (assuming that the answerer hasn't received any other votes that day) will contribute toward the answerer's overall reputation.
It's true that certain questions—specifically, single-word requests—draw lots of viewers and hence lots of upvotes for a good (or obvious but early) answer. So I suppose that you could specialize in single-word request answers and—if you were good at them—rack up points pretty quickly. But most answerers here simply focus on the questions that interest them for one reason or another, and let the points fall where they may. Eventually the sheer volume of answers that a person submits will translate into a fairly large number of points, even if (as in my case) the answerer's upvotes-to-answers ratio is quite low.
As for spending every waking hour on EL&U, there certainly is something intoxicating about researching and answering questions here and then seeing the slow drip, drip, drip of upvotes accumulate. But I can stop any time I want (famous last words).