Absolutely true, the issue exists in many code-bases and organizations. And even trying to keep things decoupled will only help so much. A 10+ year old codebase

Absolutely true, the issue exists in many code-bases and organizations. And even trying to keep things decoupled will only help so much. A 10+ year old codebase which is mostly driven by new feature development will very often have accumulated so much cruft and workarounds that trying to make and further modifications is rather likely to break something else.