I'm trying. I wrote AutoScreen (
http://www.16software.com/autoscreen) about a year ago, and I'm getting 2-3 sales a month -- the majority of those sales seem to come from small businesses -- with $0 in advertising (can't afford it, to be honest). I've been kept fairly busy adding new features for my users, but it's time to focus on another app, because 2-3 sales/month is definitely not enough to survive on.
For me, the hard part is coming up with something "worth" taking the time and effort to go through with. I've had some ideas -- but I want to do something unique, that has a chance to really take off. But should I target the everyday user, or should I target businesses (who are less likely to pirate, from what I read)? Should I make something that has the chance to be wildly popular among all computer users, or that is targeted towards a niche audience?
The good thing about knowing how to program, though, is it's essentially all you need (besides a good idea) in order to make a living on your own.
Of course you need some other skills, such as marketing, but it seems to me, if you've got a program that does something that people think is useful enough to pay for, you're set.
Looking forward to what you guys have to say. For what it's worth, I also posted this topic on reddit (http://www.reddit.com/r/programming/comments/8f4dk/any_progr...) about a week ago.