> Learning what though? When I wrote software I learn the domain, the problem space, the architecture, the requirements, etc

You don't learn these things by writing code? This is genuinely interesting to me because it seems that different groups of people have dramatically different ways of approaching software development

For me, the act of writing code reveals places where the requirements were underspecifed or the architecture runs into a serious snag. I can understand a problem space at a high level based on problem statements and UML diagrams, but I can only truly grok it by writing code.