No, never-invent-here (aka extensive 3rd party library reuse) is orders of magnitude worse. NIH means you retain full control of your codebase. It's really determinism that leads to you being able to make reliability/robustness, availability and security guarantees.

Never-invent-here is a disaster waiting to happen.

External code is better than internal code because you can reduce it to internal code just by forking it. If it is even minkscully useful, that's a win.