Comment by NomDePlum

Seeing this exact effect where I am currently working. Main available CI/CD tool is a customised and centrally managed Jenkins fleet. It's pretty much impossible to avoid using and seldom needs changed - until it does. Some attempts have been made at centralised libraries and patterns - but even that requires knowledge and study that most won't know is available or be given time to acquire.

So when the inevitable tweak or change is made it's made in the easiest, cheapest way - which is usually copying an existing example, which itself was copied from somewhere else.

I see exactly the same in other teams repositories. Easiest path taken to patch what already exists as the cost/benefit just isn't perceived to be there to worth prioritising.