Many of the comments on this page indicate why endurance sports are popular: "I GREW UP PLAYING [hockey, basketball, taekwondo another contact/competitive sport]"
Once you get into your forties and fifties you can't compete or even play in many sports against people in their twenties due to fitness/energy and it may be hard to commit to a specific evening for a club night every week.
Running, Cycling, Swimming can be done at anytime, can get you outside, can be easy on ageing joints, and you can compete against/compare your performance against yourself (how much did I run last week?, how fast did I do my morning circuit compared with last month?). They are also pretty good aerobic exercises that let you live longer.