I think that part of it is that many people are not familiar with classical music...or at least not past the basics. They know who composers like Mozart, Beethoven and Bach are...and they can identify 'the greatest hits' of those sorts of composers...but past that? Unless a composition ends up in a movie score, I don't think many people these days really take the time to get into it and actually explore it enough to know which composers and periods might appeal most to them.
I think part of the fault for that, actually, is the school system. Music education is one of those things that fell by the budgeting wayside 20 years ago...and what was warned about back then has now come to pass - we have a couple of entire generations who are really, really unfamiliar with classical music past the basics. And who really, can completely educate
themselves on such a huge body of work? I mean, where to start? People complain because it is difficult to catch up on 700 episodes of Star Trek! Yeah...well, try and educate yourself about classical music from scratch and find the particular niches that appeal to you! Good luck with that!
Part of the problem also, IMO, is that all the other media has simply crowded it out. I myself got into classical music through my grandmother, who used to listen to the Metropolitan Opera every single Saturday afternoon on the radio. She did not miss a week. I have very vivid memories of sitting with her and listening...and her 'educating me' about opera. She herself came from a strong musical background and married into one as well - my grandfather was a member of a Big Band and I have two uncles and a cousin who are professional classical musicians. Further, my mother took all of us kids to classical music performances whenever possible. So music in my family was very important.
But these days? Who has a grandmother like that, who sits with her grandchildren around a radio on Saturday afternoon, educating them about opera? Whose grandmother even has time for such a pursuit these days? Shoot, when my nephew expressed interest in classical music, I went out and did two things - a) bought him an iPod and loaded it up with classical music from my own collection and b) got us season tickets to the symphony. We've now been going to the symphony for 2 years and have I have recently renewed for a 3rd season. But he tells me he is the ONLY kid in his school (which is an advanced placement high school with a very strong music program) who goes to the Atlanta Symphony regularly. And we are one of the fortunate few who live in a city where a decent symphony is available!
And the thing is, kids can't come to like what they never hear.
Finally, I think classical music requires more of an attention span than does rock, pop, country, etc. It takes an attention span to listen enough to find the composers and periods you like...it takes an attention span to read about the composers and the compositions so as to fully appreciate what one is listening to...and it takes an attention span to listen to entire compositions and digest the musical themes presented.
And attention spans, quite frankly, are not what they used to be.
It is much easier to listen to music that is easy to listen to - rock, pop, and country. Catchy tunes, predictable licks. I am reminded here, actually of a line out of the movie
Amadeus (which I have seen countless times, despite the historical inaccuracies). When one of Mozart's operas fails, Salieri says to Mozart "You don't even give them a big 'bang' at the end, to let them know when to clap!" Mozart is appalled by this comment...but it's true of today's audience as well. Mozart may very well be one of the most incredible men to ever live. But not everyone is capable of recognizing that. And of those that are, not everyone is interested enough to recognize that....because to do so takes more effort than they are willing to expend.
I was one of the fortunate ones to have been brought up in an environment where classical music was important. I love rock (preferably alternative rock with heavy bass so I can crank it up in my car!)...but I was raised by people who loved classical music (and really, the arts in general), and so I had an advantage.
I'm glad for the education and appreciation I received...and I am trying to pass that down to my own family's next generation...but I think it would have been very much more difficult if I'd not had the influences I did while growing up.