You're keeping the Mosaic you say? Heck, I'd take it off your hands for $50! ( )
I was just talking to a friend about a related, but milder, phenomenon: You don't "lose" some artists, but you don't feel a need to listen to them anymore, either. Particularly rock artists. There are some that I still respect, probably always will, but their music is so deeply engraved on my cortex that there's no need to actually PLAY their albums, and hasn't been for quite some time. The Beatles, for instance. Most Rolling Stones too; early Dylan...all stuff that I still think is GOOD, but there's no reason to play it other than so my kids will know who they were.
I've been at about that point with Miles Davis as well. Davis was my entry-point into jazz, and from about 1979 to 1982 I pretty much listened to him and almost no one alse, jazzwise. Now I find him the least interesting major jazz figure, at least as for as listening goes. Mind you, I still think Kind of Blue is one of the best albums ever recorded (at whatever speed) and still put on Walkin' or something once in a while, but I haven't played him REGULARLY in many, many a moon. But I don't think of it as "losing" Davis so much as putting him on a backburner. Or, better yet, putting him on the upper shelf of my metaphorical bookcase of cultural artifacts. Ya dig?