We're already seeing chip amps and digital amps popping up everywhere.
With so much music available for sale via internet, keeping up with it all would be a full time job, let alone a hobby, let alone having time to enjoy it. It's really just another variation of radio, but instead of picking your favorite station from an ever increasing list, you'll pick the songs themselves. At some point it'll be too much work for most folks and for them, there will still be radio.
Perhaps a bigger effect on music has already been seen. A hundred years ago virtually everyone was "musical" (they could make music). Before radio or phonograph people sang, or played something, anything. Now with pre-recorded music, music itself is almost entirely a spectator event. Now we're embrassed to sing in public, like at church or in the car. Amateur civic bands have all but died out.
An even bigger trend in modern Western culture is the overwhelming amount of entertainment that available. We have 500 TV channels where once there was 3. Plus we have VCR tapes, DVD's, and all the pay per view movies. Radio was once just AM, now we have FM, XM, and cable. Used to be we played sports, now we watch multiple channels of all sorts of games. Kids used to play with a couple of balls, now they have a variety of game machines, PC's, internet, and TV (and they're still bored). The average adult doesn't just drive a car, he/she has to listen to the radio and eat/drink or more. And who reads without the TV or music on?
We've become addicted to passive stimulation.
And we've become information sponges, with no room left to think creatively.
jeff
