@boomerang,
You might have something, like how pork tastes nothing like it used to because we use different pigs. Milk is a commodity now, and it is all about money not taste. I think in this state all milk gets mixed at the dairy, so better cows making better milk would be pointless so no one tries. I was told that it works like gasoline, where every brand comes out of the same tap at the pipeline, that the only difference between Chevron gas and Safeway gas is the additive package that is mixed in as it goes into the truck. The gas is 99% the same stuff. With dairy there is different brands, but all the milk comes from the same place, the same cows/farms/machines.
A few years back I was eating at my favorite restaurant and I was stunned by how good the butter tasted. Turns out that it was organic butter from a particular farm that the restaurant bought at Pikes Market. My theory is that they use high quality milk from high quality cows and that it makes better butter than anyone can make with milk from the mega dairy. I would further guess that these are heirloom cows.
SIDE STORY: from about 1950 to 1971 my grandpa raised a kind of pig that had gone out of style. It made spectacular bacon, and since he had a small farm he did not raise much and he was able to sell his pigs to people who cared about such things and make money. I can well imagine somebody keeping a small band of old cows just to make great old style butter.