Shakespere’s works weren’t legally published in his lifetime. We know of them at least in part through bootlegged transcriptions.
The works of Edgar Allen Poe and Mark Twain are public domain as well as those of Charles Dickens. Doesn’t seem like they’be been “cheapened” as a result. Unless you think it has stagnated theater and cinema.
Broadway seems locked into a fascination recasting old movies with ironic casts these days rather than developing any “compelling” content.
Actually some of Twain’s work is still under copyright. The letters for instance.