Here's an interesting interview with Daniel Harrington, part time Indy Lights driver over the last few years. Freakonomics Radio did a show about the upsides of quitting, and Harrington talks about weighing the upsides of quitting racing.

No doubt there's a lot of upsides to quitting racing. However, what the economists don't consider (not surprisingly) and what Harrington only seems to touch on, is that racing is a sport driven on passion, which is not measurable. If my passion for racing wasn't there I wouldn't have even bothered starting racing. Humans are emotional beings and can't always just follow the most logical and rational paths. That applies to racing and many other things as well.