I really don't know what musicians we'll be missing in 30 years when they pass (Mick Jagger and Keith Richards may still be alive!). It's a different landscape though now with so much fragmentation and ubiquitous access to so many different artists. Pre-www most people only had access to big artists that made it to top 40 radio and your local department store's music section. Those big artists often had the ability to keep turning out good music and they became entrenched in our memories. Now it seems 98% of rock/pop/R&B/hiphop that most people have heard of are one hit wonders that disappear as quickly as they emerged. Disposable culture/consumerism. I can think of a good handful of "big" artists of my generation that will be missed (Prince, Cobain, M. Jackson to an extent...they're already gone). But I'm middle aged by statistics and really don't know what 20somethings point to as great artists. They may just have a completely different relationship to music in general except for the rogue revivalists or singer/songwriter clones.