As for later ages, I'm not sure about this but I assume serfs and village folks didn't really interact with monks and elites. So they kinda did their thing and built various contraptions and came up with ways to manage their crops...

But perhaps the local priest had a bridging effect?

I wonder how much the codex writing isolated high class actually openly looked at common folk practice to learn from or they were too proud for that.

I mean I can see for example that religions have lots of practical rules on agriculture or rules of animal slaughtering and so on, so you may be right that it wasn't so divided from early on.

This is one of those topics where I feel things are complicated. The relations of high and low culture and knowledge and the transmission of ideas between elite musings and common mundane practice is something that really interests me but I don't even know how to learn more about this.