I imagine there might be a few vigilante attempters out there, but realistically, it wouldn't last long. A lot of the circumstances leading up to successful vigilante careers are necessary, not just optional. An extremely strong motivation, lots of training using that motivation, being able to push past your fear of getting hurt and the fight or flight response, the ability to keep yourself in room and board even while staying up all night on the off-chance you'll catch a crime in progress, being in the right place at the right time(or knowing where the right place to be is), and then being able to not die if someone shoots you or the numbers aren't on your side.

Those are pretty exceptional circumstances to all line up just right.

A lot of the time, a heroic action is more of a spur of the moment kind of thing, I think. In real life. Possibly because the average untrained person is not often actually eager to put themselves in harm's way when they spend a few minutes thinking about it. Or even if they are willing, the hesitation still stops them from succeeding. 

I am surprised there's fewer unsuccessful attempts, but maybe that's just being overly cynical.