Sometimes a person will stop posting because they simply don’t have much time, they lose interest, or just don’t have much to say. While they may be missed by other posters, that’s just the way things go sometimes, and it doesn’t mean it’s a problem.
If someone leaves because they were insulted, angered, hurt, put off, or similar reasons, that is a problem. It would be a shame if “coffee addict” leaves for any of those reasons. Speaking for myself (and surely others), thoughtful posts are something I enjoy reading, whether or not I respond to them.