Not sure if you refer to the mode of thinking on my post, or the thinking that causes the "reinvention of the bridge."

Not Invented Here would be rewriting bridge4j because you feel like it. A good software engineer does research, and invents what needs to be invented because it doesn't exist. If it exists and it's freely available, you use it and write glue code.

The reason web startups can pop up so quickly is because we all do this. IndexTank was an example, the list of open-source technologies we used is very long. Big companies on the other hand are prone to unnecessarily rewriting stuff, sometimes just to keep developers entertained in between meaningful projects.