Dear Jeff: In the early 1960's, I started buying Welles' Radio shows, on reel-to-reel tape, from an outfit called Radio Yesteryear, at Croton-on-Hudson, N.Y. They claimed to be custom transcribing from original glass and acetate air checks. They were bought out by Amiri's Radio Spirits, who then had or put everything on casettes. A couple of years ago, Amiri retired and sold his operation, and the new management is now is putting everything on CD.
My guess is that the original copywrights have expired, but the process of transferring the material from one format to another may protect companies like Radio Spirits.
Welles complained about how much of his stuff was bootlegged, but on the other hand, if the Radio Yesteryear types had not collected the glass discs in the 1950's, we would not have it. The shows would have been lost. As it is, thousands of hours of many shows are gone.
The later companies have done some restoration work on many of the shows, eliminating static, minor goofs, and groove clicks, anathema to purists, perhaps, but easier on the ears of modern listeners, and closer to the original experience. Bringing up the bass a bit is usuallly helpful, too.