If you don't think so, just use a plain language without any framework, module, library or third party component and let's see who target the release date first.
We are paid not to build beautiful or robust software, but, first, to deliver faster and without headache. Decoupling stuff and avoid redundancy is a huge benefit and we experienced it dropping down the delivery time by at least 20%.
Its about developers spending time on what they think needs to be refactored due to the engineering itch on an already functional and maintainable code. Most times by doing it they can be introducing instability to the whole system. In a larger code base with handful of engineers and teams it becomes a bottleneck to make quick changes since it can break others stuff so too much interaction and policy around it and so forth.
A new shared dependency is worse than duplication. Sometimes developers get carried away about doing it the right way and don't understand the trade-offs you need to do to make it tick. FYI - I am a fully hands-on manager.
If you truly aspire to be a manager you need to understand that tech side alone doesn't cut it.