How does that explain the other contrarian phenomenon of developers hating to use existing code from elsewhere and preferring to reinvent their own wheel or polygonally-shaped solution to an existing problem?
I am the only developer I have ever encountered that even vaguely fits that Not Invented Here description, and I have been doing this for almost 20 years. This might have been more common decades ago but now the opposite is far more common. With things like Maven and NPM nobody in the corporate world writes original software anymore. The emotional insecurity is too high and leadership is too absent for modern developers to write original software.