I’m quite convinced dairy prices are driven entirely by market forces, BECAUSE they differ across brands and locations within the community.
The same way the price of gas DOESN’T.
Milk prices are manipulated more than gasoline:
https://www.ams.usda.gov/rules-regulations/moa/dairy
Oil, on the other hand, has millions upon millions of dollars behind getting it from the ground to a refinery to your gas station pump so it is convenient for you to bitch about the price.
Given the moratorium on building new refineries in this country, we are left with a gasoline pricing system that ebbs and flows with the market and supply and demand.