In the spring of 2013, Swarthmore surveyed its alums from the classes of 1994, 1998, 2002, 2008, and 2012. In the class of 2008, 75% either had earned or were currently pursuing advanced degrees 5 years after graduation. That percentage increased with each earlier class to a high of 90% for the class of 1994. These figures are probably higher for Swarthmore than for most other elite schools, but it’s broadly consistent with the figure cited by other posters that about 3/4 of Harvard alums eventually pursue advanced degrees. That doesn’t mean 75% go straight to grad school, however. Many work for a year, or several. A majority of students in top law schools work for a while before attending law school. That’s probably even more true in top MBA programs, where actual business experience is generally viewed as an admissions credential. Many delay grad school by design; at graduation, they plan to enroll in grad school at some point in the future, but either want a break from academia or want to pursue particular job opportunities, or both, until they’re “ready” for grad school. In other cases alums initially don’t intend to pursue graduate degrees, but fall back on graduate education when a first career doesn’t pan out, or proves less interesting than initially imagined, or they want to re-tool with particular skills and credentials, or they’re seeking to enhance their earning power.
Given all that, I don’t think it’s a big deal for a newly minted alum of an elite college not to go straight to graduate school. Most don’t do so immediately, but most will eventually, and for those who never pursue graduate degrees, it’s usually because they’ve managed to carve out successful careers doing something that at least supports them and in many cases they want to make their life’s work. Graduate school is always there to fall back on if things don’t work out in the music industry.