In 2004, Donald Davis and fellow scientists at the University of Texas made an alarming discovery: 43 foods, mostly vegetables, showed a marked decrease in nutrients between the mid and late 20th century.
According to that research, the calcium in green beans dropped from 65 to 37mg. Vitamin A levels plummeted by almost half in asparagus. Broccoli stalks had less iron.
Nutrient loss has continued since that study. More recent research has documented the declining nutrient value in some staple crops due to rising atmospheric carbon dioxide (CO2) levels; a 2018 study that tested rice found that higher CO2 levels reduced its protein, iron and zinc content.
While the climate crisis has only accelerated concerns about crops’ nutritional value, prompting the emergence of a process called biofortification as a strategy to replenish lost nutrients or those that foods never had in the first place.
Market requirements are not necessarily driven by capitalism.
Throughout history, needs of the culture determine the plant breeding efforts. Often flavor and nutrition have been traded for yield and storage.
For example the absolute worst watermelon I ever ate was in Uzbekistan. The soviet’s created a long-storage melon that lasts up to 10 months. It’s was about as bad as eating cardboard.
At a fundamental level the “need” for a long-storage watermelon developes out of capitalism, not a populace’s needs.