The sense of discovery is one of the biggest emotions in music these days. It doesn't matter how many people have already known about something, if its new to you then its the greatest thing ever.
I think this is great for reissue compilations and such. Some music is truly hard to come by, especially in the digital age, where the concept of crate digging is fairly abstract. It's nice to have a familiar face (Finder's Keepers, Death Waltz, Soul Jazz, etc) guiding us to lost gems.
For me, it gets problematic when this principle is applied to current music movements. I'm sure getting older has something to do with it, but I'm appalled at how much new house/techno music is merely an exercise in emulating the sounds of the 90s. Trouble is, it was a new development back then. Now, people are disturbingly content with compromising an original musical statement, simply because of the coupling of novelty and convenience.
Fortunately I can take the above with a grain of salt, as I've become jaded on being jaded. There's always something great out there...