Those who take knowledge of history and are fantasized by it will take actions to emulate dead cultures and lost pride. History itself imposes a threat on the present by idealizing the past and thus giving people self-realization of what they are capable of doing.
Retrospective view of History will give those a brief lesson of mistakes that lead to the downfall of that culture. Indeed, those who ignore history is doomed to repeat it, but these individuals will have to be fantasized by self-realization to be able to recreate something out of a event of the forgotten past. We could say this better,: "Those who ignore history is doomed to repeat the mistakes." To create a never dying culture unlike the exemplar that individual dreams of emulating, he will have to look to the past in order to spot the contradictions that lead to it's destruction.
Although this may be true in some cases, most people do not fantasize about recreating lost cultures. If we look throughout American History, we can find several examples which can disprove your theory. One can not simply learn the mistakes of history without learning all of history. Everything must be taken in context. If we understood why Hitler came to power but not what we did to cause those circumstances, how much do we really know? Taking anything out of context allows room for misinterpretation and that is where mistakes are made. In conclusion, unless you learn all of history you can NOT accurately learn from the mistakes, and even among the very few who wish to emulate historical cultures, even fewer have the means to bring their fantasies to fruition.