Though not business related, but speaks to what happens when you lose people with knowledge and insight.

When I read David Halberstam's "Best and the Brightest," one of the things that caught my attention is that US had purged all the folks who had deep knowledge of that region after the fall of China to Communism. The "China Hands," were dubbed as Communist for telling it as they saw it that Chiang Kai Shek did not have the support in the rural China to stay in power. They were run out of State Department and blamed for China becoming Communist.

So what?

When US goes into Vietnam, they have lost all the knowledge and insight of that region in the State Department after the purge and became dependent on military people who did not understand that region and grossly underestimated the strength of the enemy and exaggerated the successes they were having. The rest is history, as they say.