Access to milk is a great thing, because you get the calories and many nutrients needed to sustain life, and all you need is a cow, goat or sheep (which is mobile) and pasture.

Compare that to cereal crops like wheat or maize or vegetable crops, which require long uninterrupted growing seasons and irrigation.

Why is this important? When a troop of rampaging soldiers cuts through your village and pillages everything in sight, you grab your cows and family and boogey out of there. Essentially, you have a mobile food supply.

In the event of a drought, you have options as well. With wheat or vegetables, no rain == no food. With a dairy animal, you go kill the guy who controls the next pasture and let Old Bessie the cow feast on the grass. (The other key development was the introduction of potatoes, which remain buried under the ground safe from the rampaging army above -- my Irish ancestors subsisted on potatoes hidden from the English taxman and a cow that lived in the house.)

In Europe and the Near East, these things were really important, because there was always pillaging armies marching across the continent. Today, it's unlikely that some Mongol horde is going to loot my supermarket, so I drink milk and eat cheese because they are really tasty.