Is it structurally lacking or just culturally? You can get a bunch of kale for $2 in most grocery stores. Garlic, beans, turmeric, none of these are particularly expensive or hard to find.

Both. In few countries the industry managed to convince people that healthy food, especially vegetables, should be more expensive.

Secondly, in some countries there are food deserts or a small selection of healthy food among a lot of unhealthy one (e.g. stuffed with oil, sugar, fats etc)

Finally, the ratio of carbohydrate-to-vitamins is increasing in many foods due to artificial selection and increased CO2 in the atmosphere.