“Cave men” existed ages and ages before the people we call “native Americans.”
You have left out Eastern/Asian civilization when you say there were large gaps in the development of civilization. For instance, during the so called “dark age” of western civilization, China was experiencing a golden age of progress under the Tang Dynasty. What about the Persian empire, the Angkor empire, the Byzantine empire, the mesoamerican empires?
Scroll down in the link to the timeline and you can see all of the civilizations all over the world.
World History Timeline | Essential Humanities
The dark ages were from around 500 -1000 CE, only about 500 years (which were only “dark” in one part of the world.
Dark Ages (historiography) - Wikipedia
Even within western civilization, you jumped from the dark ages to the enlightenment and skipped the Renaissance...?
Anyway, what does this have to do with evolution? Even if a worldwide dark age existed, why would that disprove evolution?