History Repeats Because Everyone is Already Trained

 Training works, but Revenge is Sour; everyone is already fully trained in everything they're willing to be trained in. With the internet it's easy to see that everyone can afford all the training they're willing to undergo, but there's some sort of feedback which ensures everyone is already fully trained in all times and in all places. Perhaps all affordable training is already carried out at all times, idk.

 Because everyone is already fully trained, history cannot teach anything. In theory folk can learn history and, while it's hardly guaranteed that this will produce good decisions, it would at least produce different decisions. At worst, all the bad decisions would get tried, leaving only good decisions in the pool.
 However, training folk to make different decisions is impossible because the training is already capped. All adults are already making the best possible decisions they can possibly make.
 Thus, history repeats. 

 All you can do is breed a better race.
 Except you can't do that either, or it would have already happened.