The stock photo industry is getting bigger, while profit-per-photo is plummeting. There are still a number of well-known photogs in this space, some of whom are doing remarkably well for themselves.

My impression of that industry is that it's all about process - to make a living doing it you need to have an extremely streamlined process and churn out a vast amount of work.

This guy makes more than a living (from the look of things):

http://www.youtube.com/watch?v=VYkNKP96b84