Sunflowers were ornamental. Health consciousness has made people search for fats other than the traditional ghee and vanaspati and sunflower oil is one of the so called "healthier cooking oils" which explains why the sunflowers has moved to the limitless acreages of fields from our modest garden flower pots. I believe sunflower is used in making bio-diesel as well and if bio-diesel catches on like the CNG has in India, it will do to sunflowers what the bio-diesel rush in west has done to corn.
Till that happens, I think the most obvious thought in the mind if a farmer would be "I grow sunflowers and there are so many bees on my flowers, I might as well start a side business of bee keeping."