Steinbeck, Hemingway, heck let’s add Faulkner. But James (I assume you are talking Henry James) I believe he was dead by the time “The Grapes of Wrath” was published.
I assume you also meant Henry Miller for Miller? Uh, his work (if you’ve ever read any of it) was not depressing, it was smutty and very much purposely trying to shock folks but it was depressing only in that it was rather unremittingly on a low-level.
I also don’t think he or they were trying to “change public opinion”. Henry Miller often didn’t have a dime to his name and lived off of Anais Nin who gave him money her banker husband earned. And had all kinds of s-x with Henry Miller and other unders her hubby’s nose, poor sap.
Actually, I hope you didn’t mean Henry James, he’s too decent to be called a progressive, and besides, he lived from 1843 to 1916, he was “Victorian”. His novel “What Maisie Saw” is, in my opinion, the most searing critique of thoughtless adults seperating or divorcing as seen through the eyes of the child. No wonder the lib/Hollywood establishment never makes a movie from that one...