From what little I know, which aint much at all, on the subject of ancient timey type farming...
Do What Great Great Great Great Grandaddy Did was the height of technical advance at the time.
Primitive farming techniques would be grossly affected by even small changes in weather patterns.
Seems to me that it’s rather amazing that civilization collapse events weren’t even more common than they were.
I wholeheartedly agree. European society grew during the Medieval warming, and then literally fell to pieces during the sudden onset of cooling that followed (the “Little Ice Age”).