Have you ever worked directly with customers? Even those paying huge amounts of money for custom software usually don't know what they really need. They usually know their problems, but even then it can still require a lot of exploration to get to the core of it all, and then design an appropriate solution; not to mention having a good awareness of how software actually intersects with real life rather than how a non-technical customer imagines it does.

I know we're getting closer to robots that can do all that but I don't believe we're there yet.