The incumbants Goodreads and their owner Amazon have indeed done such a poor job at this. Seven years ago I tried creating a basic graph using collaborative-filtering (effectively using our actual reading patterns as the embeddings space instead of semantics [human X likes book Y so likers of Y might like other things that human X has enjoyed]). It works well to this day (ablf.io) but the codebase is so ugly I've not had the bravery to update its data in a couple of years.