There was a something a while ago on the Beeb (it might have been the Culture Show) concerning musical subgenres and the effect the internet has had upon musical taste.
In the 'old days' before the internet opened up music purchasing (or stealing) the average consumers taste was limited by the traditional mediums of radio and the high street store. The high street store only stocked a certain level of popular music, at a certain cut-off point, most things weren't profitable to sell and so were only available to the die-hard underground through mailorder. All obvious really.
The explosion of MySpace, YouTube, P2P sharing and blogging may have created a disposable culture, but its also made sub cultures and sub genres of music much more widely available. The cut off point of profitability no longer matters, even your 'high street' stores of the net like Amazon have an amazing scope of music.
So your earlier concern about only popular music (the crap on daytime Radio 1?) being remembered will no longer be a real problem as more and more people find their own niches to listen to. Eventually everyone will be in their own little sub-groups of interest, with little mainstream left to speak of.
I was watching a program about the Old Grey Whistle Test last night, and it brought home just how small musical taste was in the 1970's - this single show on the BBC was one of the few access points for many kids to discover underground alternative music.
The digital revolution has been a good thing for the freedom to explore, as long as you are willing. Its cultural footprint is immeasurable.