>> It assumes people in very different places for 1,000+ years did the same thing and had the same views
> But that was true, wasn't it? The Dark Ages started when Christianity spread through most of Europe. And really completely ended only when the Reformation fractured it.
1. Political, economic, cultural, and even religious systems would vary drastically by place and time in Europe. The lifestyle and thoughts of an English peasent in 600CE would be drastically different from the lifestyle of a Spanish or Frankish one, and would differ even more so between 600CE and 900CE.
2. The "Dark Ages" traditionally started when Rome fell in 476CE, long before Christianity had spread outside of traditional Roman lands.
3. The Reformation didn't start until the 16th century, long after the Dark Ages are considered to have ended. Generously you could say it started with the Hussites in the 1400s but that's still skipping over the Renaissance entirely which is the absolute latest end for the Dark Ages since the whole point of it as a historical context is "rediscovering" the Classical works.
> 1. Political, economic, cultural, and even religious systems would vary drastically by place and time in Europe.
This is a non-answer. Yes, political systems were different. The ARE still different.
But during the Dark Ages, there were NO places in Europe where science or scholarship really flourished.
> 2. The "Dark Ages" traditionally started when Rome fell in 476CE, long before Christianity had spread outside of traditional Roman lands.
It should have started around the time of the move of the Roman capital to Constantinople. By the time of the fall of Rome, the Darkening had been in full swing.
If you want a precise date, I propose the date of murder of Hypatia in 415 AD.