I spent a lot of years with people like these. I have a daughter who spent more than a decade in club gymnastics; she is now a Division 1 college scholarship athlete (that means a full ride, all expenses paid). She's at the tiny tiptop of a pyramid of athletes who did not and will not make it that far.
The vast majority are just not talented enough. Sometimes they're talented but not durable (yes, there's a good possibility of injury, of course). Sometimes they hit puberty and decide they're going to throw it all away and get a boyfriend/girlfriend.
Spending your own financial future on this long shot is stupid, and it doesn't have to be that way. Even with an expensive sport, there are "Mustachian" workarounds, and we used them all. For instance, we cleaned the gym where our daughter trained in exchange for her coaching fees. Almost every sport has some trade out opportunity like this; coaching, officiating, whatever. We sometimes sent her to meets with her coach and we didn't go. Sometimes we got up at 4 AM and drove 4 or 5 hours to make a meet while she slept in the car.
All of those things increased her odds of success, I think. When the whole family is mopping gym mats on Sunday night for you, that's real and fosters commitment.