The root cause of writing unnecessary code is the way the work day and compensatory systems of the modern workplace are structured. Employed software and infrastructure engineers are not paid to just drop in the simplest, most appropriate solution, do the minor customizations/reconfigurations that may be needed, and get out. They're paid to be in butt-in-chair for at least 8 hours per day, and the presumption is that they're engineering that whole time. In reality, places often must make up tasks to keep their employees busy, and using the most efficient solution is disincentivized, because you have to say you're doing something for those 8 hours.

I think the fact that we have the white-collar workforce organized after the assembly line pattern is the primary cause of unnecessary, borderline intentional complication, which includes mixing in unstable/untested components. If we could find a way to compensate engineers fairly without monopolizing their time, we'd be much better off, because the need to continually invent additional work for oneself would go away.

The bliss of a stable, low-maintenance project can be had through side projects, which often work fine for years with minimal modifications. It's really rewarding to go back to the same utility that you've written and know that the comparatively little quantity of time you spent on it is still paying dividends years later. There's an awesome sense of pride attached to that.