Comment by thechao

As a project gets larger the cost of owning a dependency directly begins to outweigh the impedance mismatch between 3rd party software & software customized to your project.

I've got 10 full time senior engineers on a project heading in to its 15th year. We rewrite even extremely low level code like std::vector or malloc to make sure it matches our requirements.

UNIX was written by a couple of dudes.