I've got to plug Marston Records. Ward Marston (world famous remastering engineer for 78s) has a small company which limits CD production to 1000 units each with very extensive research booklets. He sells CDs at $18 each. They generally consist of 1900-1950 recordings by opera singers and pianists. Each CD may contain $50,000 value of 78s or even unissued recordings from the vaults such as Edison's 300 trial opera recordings on discs from 1910-1914.
These will never appear on streaming without his permission. He also remasters for major labels, NAXOS label and the defunct Romophone (similar as his Marston label, different recordings).
It would be a terrible and historic loss to be unable to retrieve (enjoy) the greatest serious music recordings of the first half of the 20th century through CD reproduction.