Amazon Music has Back from the Vaults, "rare, reissued, and hard-to-find recordings". They are gathering up the rights to sell discs that are out of print, and then selling them in CD-R and MP3 format.
I've thought for a long time that the Recording Industry should have done this themselves, maybe with a "music.com" domain name, make it possible to buy a legal CD-R of any album ever issued ever. But, of course the RIAA et al are too stupid to do something like that.
So it looks like Amazon is going to do it instead.