Seems a tad bit disingenuous, only because the Ivy leagues are probably not competing for the top 100 QBs or top 100 point guards or top 100 pitchers either.

To me being the best quarterback at your school and playing varsity football for four years should basically be considered the same way, as you point out, being the top bassoonist would. And my guess is that for the vast vast majority of cases extracurricular activities are pretty much all created equal unless you do it to a degree that makes it notable (like being an all-state athlete, or playing with you regional symphony or something)