Why don't High Schools teach modern music?

Most High Schools across the country have classical music programs.  Most of these music programs provide students with one of three options: Concert Band, Orchestra, or Chorus.  Why don't they teach modern music?
 
The short story on the purpose of music programs, better explained in the national standards for music education, is to teach students how to read and notate music (time, tempo, the staff etc), basic music theory (keys, scales, progressions etc.), perform (individually and/or together as a group), improvise, and maybe even a little composition.  Naturally, students learn all this through their instrument of choice.  Therein lies the question, what is it with the choice? Modern music can accomplish these goals.
 
Concert band consists of classical music instruments: Flute, Clarinet, Saxophone, Trumpet, French Horn, Trombone, Tuba, Snare Drum, Bass Drum, Cymbals, etc.  Orchestra consists of the classical string instruments: Violin, Viola, Cello, Bass etc.  These two groups play predominantly classical music, as one would expect.  But very few high school students actually like classical music or classical instruments.  This could explain the popular “band geek” stereotype and the fact that very few teenagers ever play their high school instruments after graduation.  Modern music bands that students actually listen to consits of guitars, bass, maybe keyboard, and drums.
 
Clearly though, teenagers like the idea of playing music.  Guitar Hero was the first video game to surpass $1 billion is sales (reference) while Rock Band based the $1 billion mark a short time later (reference).  Both games cater exclusively to modern music genres.  The current top billboard hits in this country (driven primarily by teenagers) show pop stars such as Lady Gaga, Katy Perry, and Rihanna are by far the most popular, followed by others in the Hip-Hop, Country, Rock, and Dance genres (reference).  These collectively can be thought of as the modern music of which I  speak.  Classical doesn’t even get a category.
 
I’m definitely not advocating that High Schools just give in to what the students like, but there is absolutely no reason why you cant teach all the previously mentioned standards of music education using modern music songs that students like on the instruments used in those songs.  Lady Gaga songs have a key, a tempo, a chord progression, and sheet music is readily available (here, for example).  Maybe the kids would be more inclined to practice their scales if they knew that their favorite songs were composed using those same scales.
 
Granted, its hard to give a concert to proud parents with 100 guitars, 50 keyboards, and 25 drum sets, but that really shouldn't be our motivation in music education.  Plus, even the parents may get a kick out of hearing their children perform the same modern music songs that can be heard on the radio, rather than classical songs played by no one outside of school.