The reason we can't convince you of this, is because you did not GO to X; the majority of kids that attend X do NOT even play a sport-- and the vast majority do NOT go to X for athletics-- they go for academics FAR more often than for athletics. When I was there, the ONLY kids in the school who EXPRESSLY came to X for the athletics were the swimmers. X was mediocre in football then, and Moeller dominated the sport at the time (along with Princeton).
Even today, with ~120+ kids on the X varsity football team, that STILL means that less than 1 out of every 6 kids (with 750 in the combined junior and senior classes at X) is playing varsity football-- and 5 out of 6 are NOT. Add in the other kids playing golf (less than 10), soccer (~20), cross-country (~20?), and that's about 170 kids (i.e.- far less 1 in 4) are even playing a fall sport.
The numbers don't change much when you consider winter and spring sports-- especially when you consider that many of the same kids are playing those other sports, while many non-athletes are playing NONE: basketball (~12), swimming/diving (~30?), wrestling (~20), bowling (~8?), hockey (~20?)-- that's another 90 kids-- with many of them already counted once for a fall sport (e.g.- QB McCaughey in hockey), so probably less than 50 additional new kids; then baseball (~20), track/field (~30?), lacrosse (~30?), tennis (~10), volleyball (~20?), rugby (~40?)-- that's 150 more-- but with probably only ~70 new kids, since the same kids who play fall and winter sports tend to make up those spring sports (e.g.- QB McCaughey in baseball, RB Vrsanksy in lacrosse).
Even if every one of those kids only played a single sport, at MOST, you'd have 170+90+150= 410 total, but the real total is probably more like 170+50+70= 290 kids playing sports of the 750 kids in the junior and senior classes-- meaning, again, well less than HALF of all X students play a sport.