farmers choose every day whether to continue production, and for fickle and irrational reasons. ceasing consumption cannot cause them to make any decision. they have free will, so only their will can be said to cause their actions.
This must be a parody account or something. I can't imagine anyone dumb enough to actually believe farmers will produce milk to rot ad infinitum without it ever being purchased. They couldn't maintain production level without consumption even if they wanted to.
you talk about it as though there are only two people, and each only needs to make one decision: the farmer whether to produce, and a milk drinker whether to buy it. there are dozens of actors and factors.
If people stopped buying milk at current levels, then it would not be produced at current levels. The dozens of actors and factors would all be a part of that decrease. The market would shrink, not dissappear necessarily.
what caused any of those declines? could those events happen in the milk market? were any of those markets as ancient as milk? how else might they differ?
The events were that demand decreased. Yes, demand could decrease in the milk market. Whether or not it will is a separate question. They are different in that the market decreased in the former and not the latter.
how do you suppose we could decrease demand? do you have some method to accomplish this?
edit:what is the metric by which you gauge demand? price? volume sold? volume produced? futures markets? I just don't think this is a well formulated test. but if you come up with one, please let me know.
all the people involved in those markets were making decisions distinct from the people making decisions in the milk market. I dont think we can find anything so conclusive.