It's simple, mechanically non-complex, everyone can do it, everyone can take part in it. Corporations can organize running events as team-buildings exercises, you can run with their tricot and wear their corporate logos, you can run for charities and for nebulous projects halfway around the world, which you have no meaningful real physical relationship to. Everyone can run after a week of getting used to running. It's an inoffensive sport. You don't build muscles, which has problematic hierarchical implications about the fundamental indifference of the Human experience and biology. You just lose some calories. You can use running as a way to counter your snack-eating habits. Running produces the same Human body. It doesn't require a lot of consistent discipline, it doesn't require good habits, it doesn't require a diet, rich with animal protein. It doesn't even require you to sleep well. You can have a very cortisol-rich lifestyle and still go running regularly. You can feel a rush of energy without being energetic. You can feel healthy without being fit. You can feel like you do something without being capable. Running is something even the most humiliated and degraded slave from a thousand years ago would be able to do. So it's the perfect sport for a class of people, who found themselves with all of the power and the political instinct to simultaneously mirror, but also distinguish themselves from the lower classes.