Think about coffee. It’s a commodity. But more people are spending $4-5 on a single cup instead of $4-$5 on a pound of grounds. Spending power does not match price change.
A good historical case study is Standard Oil. In an effort to stabilize prices and reduce peaks, Standard oil established last mile delivery for refined oil. People bought Standard Oil at the grocery store. Standard didn’t start buying oil wells until 20 years into the company after they had pressured prices down to the bottom.
I'm not sure how anything about brands could apply. Any "brand" ends at the grate where you dump the grain.
Similar with other ag products. Remember how we just had that E. Coli outbreak in lettuce and nobody had any idea for several days where exactly it came from, so they had to broadcast the warning across the entire nation?
https://unctad.org/en/pages/newsdetails.aspx?OriginalVersion...
An oversimplified explanation would be that each buisness has an incentive to undercut their competitors and by doing so decline the profit margins for everyone.