> Of course you don't do that. You look to see what orchestras they were in as a kid, what competitions they've won, etc. You'll immediately see that most people who list music as an extracurricular are decent, but nothing extraordinary. If you are really good then you can meet with someone at the music department at the university you're applying to, perform for them, and if they think you're good enough they'll tell the admissions department and give your application a boost.
Compare with:
Of course you don't spend 3% of the process critically reading essays. You look to see what writing groups they were in as a kid, what essay contests they've won, etc. You'll immediately see that most people who list writing as an extracurricular are decent, but nothing extraordinary. If you are really good then you can meet with someone at the English department at the university you're applying to, let them read your entrance essay, and if they think you're good enough they'll tell the admissions department and give your application a boost.
The difference is that we presume the OP did take the time to critically read those essays. Imagine if OP had written, "I didn't see much in the way of extra-curricular writing activities, so I can assumed those 600 essays were boring." It's not a serious statement.
Presumably there is a web portal for retrieving the essays, reading them in the browser, making comments, etc. Presumably that web portal exists because admissions can assume with impunity that admissions officers are literate and can critically read and rate an essay according to some predetermined rubric.
We don't have that same kind of API for musical excerpts because we don't have the same rate of musical literacy we have for reading literacy. That's unfortunate because an admissions officer could tell a lot about the applicant's propensity for risk taking, sense of humor, and a lot of other important characteristics that are difficult to convey in test scores and essay form.