in the united states. This is especially true in olympic sports.
In many European countries multi sports clubs with vast adult memberships subsidize the operation of niche sports particularly with youth departments that are largely free to participate in.
If I want to fence in the united states, I have to find a fencing club and likely spend a boat load of fees and travel costs to go to competitions.
We also very much rely on intercollegiate athletics to provide training grounds for the nichest of sports. This might not be the most optimal way to identify and cultivate talent for some sports.