The hardest part of building software is not coding, it’s requirements

Yup. Different subdivisions, each with their own unique view on the matter, dozens or hundreds of documents but nobody can clearly tell you what the final rules will be. You can write a program that's 3 times as complex as it needs to be just to be prepared for every eventuality and then a new eventuality will appear out of nowhere.

It's a messy business. Mostly because all those different departments don't understand each others point of view and the top level coordinators have a view that is too abstract to be helpful.

Skilled programmers aren't even that hard to come by, but programmers with the social skills, experience and willingness to jump through those hoops are.