> If we wanted to NIH all the things, we'd have to start doing crazy shit like implementing our own JSON serializers or hand-rolling artisanal CSPRNG/SHA algori

> If we wanted to NIH all the things, we'd have to start doing crazy shit like implementing our own JSON serializers or hand-rolling artisanal CSPRNG/SHA algorithms. These two are not analogous. Writing your own JSON deserializer/serializer can absolutely make sense depending on what you are doing. You'd better have a very good reason for writing your own sha algorithm. Any sufficiently gifted programmer will reach a point where they realize that there is no third party tool that is quite right for the specific problem they are solving. The art is in identifying where exactly the line is. Personally, I tend to fall in the batteries not included camp but this only works in a high skill/trust environment, which frankly is not companies. You're probably right that in most cases preferring batteries included is a better default disposition. But almost definitionally these types of places will tend not to be technologically innovative.