Perhaps the Diamon leaders come from a super competitive cultural that frankly doesn't care that much about those that have previously failed. Its not like humans disregard what should be learnt knowledge for example how many major offensives in World War 1 were NEVER going to work, something they should have worked out the last 3 times they tried to breach that certain part of the line and failed. All because a being is capable of learning from previous experience, doesn't mean they will.
