Programs aim at usefulness, while prose aims at truth, and truth and usefulness are fundamentally different.

This means that a collection of programs has a fundamentally different structure from a collection of prose. Also, the process of creating a large program is also unlike the process of creating a large work of prose.

Programming is fundamentally about processing information - doing something. Every bit of code takes something in and spits something out.

This is very different from prose. Prose aims at truth. To make an important point which is true, and to argue that it is true, or superior to alternative ideas.

Programming is usually not openended in the way writing is. This means that things have a fundamentally different structure. (I suppose one can come up with unexpected new features, etc. But in that case, the application is openended, but its implementation is not. The implementation has only one purpose: to instantiate the application.)