Well, the diet of an Olympic swimmer is about 12,000 calories per day. Compared with the diet of a soccer player (About 3,000 calories per day). The diet of an Olympic swimmer is 4 times more expensive.
http://www.dailymail.co.uk/femail/a...elps-12-000-calories-day-dont-doing-harm.html
To this you must add supplements like creatine, protein shakes and all kinds of supplements that a soccer player or a golfer doesn't need.
To this you must add the risk of injury. In a more violent sport like rugby injuries are more frequent, more severe and therefore more expensive. And that equation results in developing a rugby player is more expensive than develop a soccer player.
This NFL player eats 10,000 calories per day:
http://firstwefeast.com/eat/vegan-nfl-player-diet/
Not all sports have the same cost. There are more expensive and more difficult sports.
I know that about Crossfit. It's just a way of naming an internationally recognized brand for training different capacities, not just brute strength or speed.
I did crossfit about 8 months and I left because I hate the crossfit culture