They tend to in practice, but it may not be completely inevitable. Organizations have some control over how bureaucratic they become.

I don't know if you meant it like this, but the original sense of "prove" was more like "test". That is, an apparent exception is a test of the rule's generality.

According to that wikipedia page, Nucor believes in decentralization and objective metrics, so they are indeed a good test of the rule. If that page is accurate, Nucor employees can't get very far on politics alone.