"We don't even live remotely close to a hundred thousand years ago"

Young Earth creationist? Going by the available evidence, our species did. The evidence could be "testing our faith", of course, if that's your thing.

"and without civilization advanced technology would likely not exist (medication, education, etc. requires society) - assuming you want/like the tech we have now."

Anarchy is without the State, not without society.

"Anarchy by definition is unstable."

Anything can be unstable by somebody's definition.