Not all farmers have it, and there's different types too. Different policy for hail/wind damage vs. losing the crop due to drought or other things.
My friend only has crop insurance to cover salary and fixed costs on an average year. Not enough to cover all losses in a bad year, such as this one with the extra $$ spend to run irrigation, etc. I don't know exactly how it works, but I don't think it will cover a poor or partial crop, I believe it only covers 100% crop loss. Last year they got paid on almost 600 acres that they couldn't plant because it was flooded. If it dried out, they couldn't plant anything on it that would result in any $$ in their pocket, but they could plant a cover crop to keep from having the soil blow away, or to have to continually spray for weeds.
