I think time is a big factor for why people leave the sport, but I also think fatigue is a factor. After 10 years of triathlon, I've been on a break for two years (initiated by injuries) and other than having more time (and money) to do other things, I'm really enjoying not being so fatigued all the time.
I do miss it though, and may do some races next year although I think I'll stick with short course. Less training time, less fatigue, cheaper, lots of fun and I'll still have plenty of time to golf, which my girlfriend and I have gotten into this year. Part of what we've enjoyed so much about golf is that we can do it together. She bikes and runs, but our speeds are very different so it's challenging for us to do those together when I'm training.
I do miss it though, and may do some races next year although I think I'll stick with short course. Less training time, less fatigue, cheaper, lots of fun and I'll still have plenty of time to golf, which my girlfriend and I have gotten into this year. Part of what we've enjoyed so much about golf is that we can do it together. She bikes and runs, but our speeds are very different so it's challenging for us to do those together when I'm training.