Another proposed title: "Why you need to be rich and have a white collar job to have time for leisure activities"
Subtext: _less than 1% of rich people are active triathletes_
Some of the people with free time and money spend it on endurance activities. Some of them spend it on watching TV.
Rich people historically do things to distinguish themselves from people who are not rich. If you ever watch a historical movie, or go to a Scottish festival, you'll sometimes see women wearing these blouses with really long, open, flappy sleeves, where the opening is so big, you could literally fit a watermelon up the sleeve. The purpose? Just to show the owner could afford that much cloth.
If a sport can be played by middle class people, rich people will either gravitate to their own subgroups in the sport, or take up a sport that middle class people can't afford. It's just people doing what people do with tribal markers.
Some of the people with free time and money spend it on endurance activities. Some of them spend it on watching TV.
For tri-athetes: (back of envelope math, 120K a year is top 5% of income in US - source: http://graphics.wsj.com/what-percent/)
Population of US is around 325 Million. 5% is 16.25 Million.
(Total membership in the USA Triathlon organization: 116K in 2015) https://www.teamusa.org/-/media/USA_Triathlon/PDF/About-Mult...)
116000/16250000 = ~0.7%
Conclusion less than 1% of rich people love triathlons.