I'd love to get $500 an hour, every hour every day. Alas, it's darned rare when I can make that. (some photography jobs,but too few).
I do, without a gun to my head, well, work driving a bus for $12-18/hour. And while not a gun, the cardboard box under the bridge does indeed provide motivation.
So if I have the gear and nothing going on, why not work for $50/hour? Sure, I won't book a saturday in october for that price..now. The week before that empty saturday ask me again.
I left my house this morning at 6:25 am and returned at 4:20pm - bus in the am, field trip and bus in the pm. Now some of the field trip time I spent sititng in mcdonalds drinking coffee and reading a magazine,but it's pointless to drive back to sit for 20 minutes to return to pick up the kids. So that's what, over 9 hours of my time traded for $120 ish.
Ya know, I'd rather DJ a school dance for 3 hours, plus setup/travel/tear down and have 6 - 7 hours invested for $200.
I also know in both cases if I demanded double the money I'd get no money, they'd find someone else to give the money to.
YMMV of course.