1. People are rarely in a position to effect changes or draw from historical lessons in the first place
2. Whatever lessons you can draw are often very contingent on the time and place and even taking into account patterns, we still end up in a situation where the lessons can't really be applied beyond general principles that are already well known without much study involved.
3. Often the understanding we think we have of historical events is hopelessly distorted anyway, and colored by the sources and narratives we have read or composed in our minds.
In the end, the people who do change history tend to barrel away at problems without taking the past all that much into account beyond some general references. Even if we take into account survivorship bias this is still an important phenomenon to consider. Hence the conclusions that there is much to learn from history is either trivial or actually under its own layer of naivete.
The idea that we all just “appear” on Earth from some formless void, then subsequently make totally independent decisions, devoid of any previous influence, is both highly naive and far too common.