Conservatism and the novel: Are great novelists reactionaries by nature?

This is probably a question for a book, not a blog, but: Why are most of the great novelists of the Modern such political conservatives? Maybe this is a gross exaggeration, but as I try to think of the major examples of those who've taken on expressly political themes, most - all? - portray those who want to change society as bloodthirsty radicals who either have no commitment to their ideas or are so rabidly and blindly attached to an ideology that they destroy themselves and others and bring no lasting justice or progress. I'm thinking about this as I read Henry James's "The Princess Casamassima," shockingly political for James, and highly sympathetic to the injustices suffered by the working classes - the 99 percent - in 19th-century Britain - and though I'm not sure where it's going it seems inevitable, as the main character is about to become a political assassin - that James is setting him up for destruction. Think also of Conrad (The Secret Agent) and Dostoyevsky (The Devils): the world view of these great novelists seems to be that the only course of action for a progressive is terrorism. There may be counter-examples - I ought to re-read Middlemarch to see, and thinking also of The Magic Mountain, which at least gives equal weight to nihilism as part of a debate on the course of history: but is there something innate to the qualities of being a monumental writer and adopting a fundamentally conservative world view? Is it the selection of who had, at that period of history, the wherewithal to become a novelist? Something about the forces of 19th-century and early 20th-century history itself? Or just a generalization that does not hold up to scrutiny?