Hmm. Self-destruction, crashing. I would see that as not being higher levels.
Who with right self-love would commit suicide or submit to alcoholism.
It does not take a polarized or high-lvl person to be at the top in a country or have high impact. Case in point: Bush.
The people who elect them and the people they lead are quite low lvl, which is why it does not take someone extreme to lead them.
Could it be that significant darkworkers of the past have decided not to go for political or military conquest, because that is a road of conflict and difficulty? Power with can be greater than power over others.
Political/military conquest is often syndromous, brings enemies, does not neccesarily give maximum mental/spiritual growth, and does certainly, by many standarts, not bring the most comfort and pleasure. Whether it is the greatest power depends on perspective.
I must confess that I do not know history well, but I will try another point and you can see if it seems true or not.
Committed suicide. An act that seems directly against high-level darkworking.
In wikip, I read that he "had a nervous breakdown", and had "shown signs of paranoia". Indication of low-lvl.
Hitler took advantage of a country in turmoil, it was a time of low levels of consciousness of the people. He had charisma to them, but in that time it took perhaps only firm courage, evoking pride, and a common enemy.
He does not seem to have been polarized or high level. He had much political/military power and enormous impact.