How many people decide whether or not the public will like a book before the public even gets a vote? Maybe a publisher, editor, and agent? These people are professionals who stake their careers and livelihoods to some extent on knowing what the public will like, and certainly they are often right.
But is it efficient to have so many steps between writer and reader? We have all heard the stories of books being rejected repeatedly before eventually breaking through into the market and becoming instant best-sellers. Even more disturbing are the minions of crappy books which find themselves on bookstore shelves just to remain there until they are tossed in the garbage (most often where they belong).