All due respect to patio11, who has made an excellent career for himself, but outside of the usual suspects (NYC, SF, Chicago), the kind of rates he talks about will get you laughed out of almost all client negotiations.
I don't like to be negative, but I just don't think Patrick's experience is reproducible without substantial amounts of luck. I have a friend who's constantly talking about lottery winners and telling me, "Look, they did it, so why can't you?" I feel the same kind of frustration on this topic.
Like, let me put it this way: If I were to create an exact clone of Bingo Card Creator the way it looked and behaved a few years back, do you think Joel Spolsky would come knocking at my digital door? I really, really don't think so. You were laughing at the idea that his "Hello World attached to an RNG" is hard to reproduce, but nobody ever thought that was the difficult part — it's the fame that followed from it that gave Patrick a base of good clients, and that seems to be harder to replicate or replace. At least that is my impression.
(Just to be clear, I don't mean any of this to disparage anyone. It's just like I said earlier — this kind of "it's so easy" talk bothers me in the same way as lottery ads.)
Businesses everywhere deal with money flows that are really big by individual-person standards. It's not just a question of being in outlier cities.