American farming is currently dominated by the system of industrial agriculture that arose in the decades after World War II—a system built around immense farms growing commodity crops, such as corn and soybeans, that are used to produce processed foods. Production of these crops is heavily subsidized, which ensures that processed foods will be cheap and abundant.
Farmers growing fruits and vegetables—known as "specialty crops" in the world of farm bureaucracy—are largely left outside this system. It's harder for these farmers to obtain credit or crop insurance, which makes their work a much riskier proposition. And if commodity-crop farmers want to branch out and plant fruits and vegetables, they may find that the terms of their subsidies actually prohibit them from doing this.
In short, policy puts fruit and vegetable farmers at a disadvantage compared to their peers growing commodity crops. If we want a more abundant and affordable supply of healthy food in our markets, we need to make it easier—not harder—for farmers to grow it.