I remember growing up (born in 75) and because of radio and MTV we heard such a tremendous cross-section of music. From Pop, Rock, Rap, R&B, even Country.
Every week we'd listen to America's Top 40 and watch the MTV countdown of the top 20 videos. During the summer we'd spend all day watching MTV just to see that one video we liked, and in the meantime we'd hear and see all kinds of other acts that we'd also grow to like whether we wanted to or not.
To this day I still know the words to "Life in a Northern Town" and "Mexican Radio" even though I couldn't tell you any other song from Dream Academy or Wall of Voodoo.
Now my kids are 12 and 14 and their music is "my" music (more or less). My son has been to 2 concerts (Rush and Porcupine Tree) that he would have NEVER gone to on his own. My daughter likes Radiohead but probably wouldn't if it weren't for me or the Twilight Soundtrack.
Even for me, to find new music I tend to just follow suggestions from people on various message boards I visit.
I can't remember the last time I listened to "Terrestrial Radio" ... and even when I did, it was the Classic Rock station not anything Top 40, etc.
There is NO WAY the future generation is going to have a good mix of different styles of music they like. My generation can get down to Michael Jackson, NWA, Nirvana, The Police, U2 (when they were awesome), Will Smith, Madonna and even "Weird Al".
So I guess the question is ... is this generation pretty much stuck with whatever their parents may listen to or that friends may find somehow? And how are people actually FINDING new music?