Enter the Russians
It was not until the 1800's in Russia did breeding create the giant. single-headed varities that are commonly planted today. Why Russia? Why did this North American plant species become fully domesticated in Russia? It all has to do with religion. The Eastern Orthodox church has very strict guidelines about what can be eaten during the Lenten season. Forbidden are most sources of fats and oils. But, because sunflowers were not known to the church when these rules were written - sunflower oil was not forbidden by the church. So, the Russian people breed sunflowers to produce oil.
In the early twentieth century, the Russian varieties of cultivated sunflowers were brought back to the United States. And since that time, the acreage of farmland in sunflower production has increased. I see more and more uses of sunflower oil - for example, Lay's chips has new packaging proudly proclaiming their use of sunflower oil.