Short for Not Invented Here syndrome... when developers ignore existing libraries or solutions and implement their own version. Usually this is meant negatively, i.e. developers thinking they -need- to implement their own version, at great expense, when they could have just used an off-the-shelf library. However this article is positing that writing your own code is a good thing in some cases.
It is a good thing in some cases for a couple of reasons - first, off the shelf libraries often do a lot more things than are needed for the project at hand which can have the same effect that adding extra lanes to a highway does on traffic - more effort in the same space that could have been avoided. Second, OTS libraries can be opinionated, which winds up bending the existing codebase in ways that aren't optimal or aligned with the other code in a given ecosystem.
