Very interesting article. I'm upper middle class and really like strength training, but not in a bodybuilding kind of way. I don't want to get big, I want to get/keep reasonably muscular, for the reasons stated in the article : the older you get, the more muscle you tend to lose for natural reasons.
For that goal, I like calisthenics. Push ups, pull ups, bodyweight squats, planks, that kind of stuff. It's extremely cheap (only needs a pullup bar) and can be done anywhere, even when traveling. I can't think of a cheaper sport, I don't even need a pair of trainers.
That's the trend. Probably will see "why do rich people love strength/fitness sports" in 20 years. Certainly crossfit doesn't include many people on the dole.
For that goal, I like calisthenics. Push ups, pull ups, bodyweight squats, planks, that kind of stuff. It's extremely cheap (only needs a pullup bar) and can be done anywhere, even when traveling. I can't think of a cheaper sport, I don't even need a pair of trainers.