I'll give it a shot. This has little to do with government. It's not clear whether songwriters, for example, are paid for the use of their compositions. Moreover, Concord (to use one example) paid the original owners of Fantasy for the recording masters. Given the timing of their purchase (at the start of the record industry's decline), it's hard to say it was a wise purchase. Surely they have the right to make money off these masters. These cheap sets make it harder for them to do so.
My assumption is that Concord still pays royalties to the musicians (at least the leaders) and for sure to composers.