It’s interesting that this thread came up now. I was just doing a little reading on Wikipedia the other day about hypotheses for the Bronze Age collapse.
Of course, the old-time theory as far as Greece is concerned is the Dorian Invasion. People seem to be less and less sure about this as evidence for it doesn’t seem to be coming in.
That would be Greek on Greek violence, but not a civil war necessarily. And in the Dorian Invasion scenario, you’d have to explain why the Dorians were so keen on the tales of The Heroic Age. Keep in mind, the two surviving books were part of a larger corpus that included the now mostly lost Epic Cycle. Those Greeks really loved the tales of the Heroic Age.
If the Dorian Invasion is out, and you don’t want to go with non-Greek Sea Peoples, then another explanation (in general) is some sort of tech revolution. Hard to justify iron weapons and such given the time line.
But one thing I read that may have happened is a change in warfare that was effective against chariots. Chariots were the tanks of the day. (Hard to imagine them being effective in Grecian topography, but they were.) Perhaps new, massed formations with spears or something were found to work against them. The warrior elites found themselves at a disadvantage to low class masses. Havoc ensues.
Chariots are mentioned in the Iliad. E.g., in the battle where Patroclus gets killed. But some say Homer (or his late Bronze Age sources) didn’t really understand chariots in warfare for the most part. “Something” happened fairly soon after the Trojan War where the rule of chariots in warfare went away.
Whether this was a cause or effect, we don’t seem to know yet.
Usually in a civil war, especially with so many states, there would be winners. And Linear B writing would have persisted somewhat. But all the big cities were destroyed. Rural vs. Urban strife? Why would the rurals all over be against the Urbans all over? Ancient Greece seems just too segmented for such widespread internal destruction.
Perhaps it was a series of events. Invasion, volcano, civil war, tech.