Frankly I'm not sure it's just the 'kids'. I'm 39 and whilst I like the Spotify service, I also like the knowledge that I've got my own music stored. I'd hate to think I'd built up a series of playlists with an online service only for them to disappear overnight for a variety of reasons
Why go online ? Just set up a media pc with a backup at a friends house in the neighbourhood (have them backup to each other). Cheap, reliable and no overnight disappearances.
I'm talking about the online service. If you rely on a service, and put time and energy into organizing what you like, then the fear is that at some point it might disappear. Possibly a little irrational, but thats why I like to 'own' and store myself
At my startup, psonar, we believe in mp3s vs streaming - particularly for the 'kids'. I sit in front of a computer all day so streaming is ok for me, but teenagers spend far more of their time listening to music away from a computer. ipods, phones etc play a bigger part for them than computers.
Its also not just economically that streaming falls down, technologically the battery life and network bandwidth isn't there either - and doesn't show a lot of signs of improving rapidly
In my mind the issue is: do people want to own music or do they want to pay for a subscription--these are not one in the same.
The point by the way is valid. People get value out of listening to all-you-can-eat music, so they would pay. The tricky bit is making the transaction simple and automatic.