The question of why pop music is nearly absent from Star Trek was taken up by soundtrack producer Lukas Kendall. Here's the relevant excerpt from his (good) long essay:
http://trekmovie.com/2015/01/11/editorial-the-future-of-star-trek-its-the-story-stupid/
Unlike the Marvel universe—which takes place in contemporary reality—Star Trek takes place in the future. And not just an abstract future, but a specific vision of the future from fifty years in the past. It’s not only a period piece, but a parallel universe—a “double remove.”
Before man landed on the moon, manned space travel was plausible. Roddenberry intended the bridge of the Enterprise to be completely believable. (Next to The Beverly Hillbillies, he was doing Chekhov—that’s with an h.) But we now know that (Interstellar and Avatar aside) interplanetary space travel is not realistic, or certainly not happening any time soon.
As a result, Star Trek is irrevocably dated. What was meant to be the actual future has become a fantasy future—but it’s not allowed to acknowledge it. Star Wars is unashamed space fantasy, set in a make-believe galaxy, but Star Trek is supposed to be real. (I guess I missed the Eugenics Wars.) Ever wonder why in Star Trek they only listen to classical music, or sometimes jazz? Hearing anything recorded after 1964 would puncture the reality (except for time travel stories). This is the same reason why The West Wing never referenced a president after Kennedy.
http://trekmovie.com/2015/01/11/editorial-the-future-of-star-trek-its-the-story-stupid/
Unlike the Marvel universe—which takes place in contemporary reality—Star Trek takes place in the future. And not just an abstract future, but a specific vision of the future from fifty years in the past. It’s not only a period piece, but a parallel universe—a “double remove.”
Before man landed on the moon, manned space travel was plausible. Roddenberry intended the bridge of the Enterprise to be completely believable. (Next to The Beverly Hillbillies, he was doing Chekhov—that’s with an h.) But we now know that (Interstellar and Avatar aside) interplanetary space travel is not realistic, or certainly not happening any time soon.
As a result, Star Trek is irrevocably dated. What was meant to be the actual future has become a fantasy future—but it’s not allowed to acknowledge it. Star Wars is unashamed space fantasy, set in a make-believe galaxy, but Star Trek is supposed to be real. (I guess I missed the Eugenics Wars.) Ever wonder why in Star Trek they only listen to classical music, or sometimes jazz? Hearing anything recorded after 1964 would puncture the reality (except for time travel stories). This is the same reason why The West Wing never referenced a president after Kennedy.