First let's get a little historical perspective. Possibly the greatest composer of all time, J. S. Bach, was cantor and musical director at the Thomaskirche in Leipzig from May 1723 until his death in 1750. As music director he was responsible for the music at all four of the churches in Leipzig. The city fathers regarded the appointment of Bach as an important factor in boosting the attractiveness and reputation of Leipzig as a center of learning and culture. One of the major results of his tenure was the cycle of cantatas in which he provided original compositions for voice and instrumental ensemble for most Sundays and feast days of the ecclesiastical year. It is safe to say, therefore, that for the ordinary citizen of this prosperous German city, the music of Bach was central to their musical experience. What made this possible was partly the religious context: most people went to church and Bach was the consummate church musician. Therefore, the cultural context of the time predisposed listeners to his cantatas as settings of texts that were predominantly religious. That they are widely appreciated today, even though that particular context is largely lost to us, is a measure of their high quality as compositions.
Perhaps the lesson to be derived from this is that most listeners are not predisposed to the abstract appreciation of sheer aesthetic beauty in music, but need, as it were, a helping hand in the form of religion or some other contextual factor. What cultural factors are present today that predispose listeners to particular forms of music? One major one is the growth of popular culture. In Bach's time there was probably little (folk-dancing?) that we would recognize as popular culture. But now we have an enormous cultural and economic force in society ranging from Hollywood movies, to video-gaming (now larger economically than Hollywood), to popular music to television and so on. The music of these various realms is mostly popular. Whereas cinema used to use a lot of classical music, it does so less and less. Ironically, the more sophisticated video games such as the recently-released Skyrim seem to be using vaguely classical genres.
In general it is safe to say that today's listener is used to popular music as the soundtrack of her life, and unused to classical music. Classical music has become the outlier, the rare, the unusual. In the 18th century, I don't think that was the case. Popular music is ideally adapted to the usages of our lives at present. It is crafted to be played through electronic systems of reproduction and does not suffer from so doing, unlike a lot of classical music. It is brief and easily absorbed. It is about the typical themes of people's lives, love, identity, repression, whatever.
What it is not, or mostly not, is of very high aesthetic quality. If I were to take a guess at where the popular music of today ranked aesthetically, I would equate it perhaps with 17th century French ballet music. At best.
Perhaps, in the future, our current pop music will look just as odd and musically constrained as this does to us. Imagine how this will look and sound to viewers two hundred years from now:
Before the tsunami of popular culture in the middle of the last century, however, there was an earlier movement: the scholarly historic developments of the 19th century. In 1829 Mendelssohn began the revival of the music of Bach with a performance of the St. Matthew Passion in Berlin. This was followed by a widespread revival of Bach's music, a complete edition, complete recordings and so on. In other words, a sense developed that great artworks were important and could be appreciated not only by their immediate audience, but by modern audiences. So now, we 21st century listeners can develop an appreciation not only for Lady Gaga, but also for Bach, Guillaume DuFay, Leonin and even Balinese gamelan music.
Here is where the notion of quality comes in. The music of Bach, for example, is of extraordinary aesthetic quality. Composers to this very day study how he composed and listeners are still astounded at the richness of his music. But for many listeners, their milieu of popular culture hampers their ability to appreciate Bach or other classical music. The juggernaut of popular culture is so pervasive that many may grow up hearing little or no classical music. It is disappearing from the public space. Classical artists used to appear more often on television than they do now.
The solution? I'm not sure I have one except that it would probably be a good idea for parents to ensure that their children get some exposure to classical music just in case. After all, if the bottom line is quality, classical music really can't be beat. Today's audiences seem satisfied with less, but individuals don't have to be.