…also, the examples @HPuck35 gives are not necessarily of a stereotypical well-rounded “jack of all trades” applicants, but rather of a well-rounded class consisting of students pursuing their individual passions at the world-class level.
Either way, the most important thing is, as @DadTwoGirls put it, not to distort your life doing something you guess adcoms want you to do just to get into a particular college.
You do you.