Ethanol is only a "viable" option because the taxpayer is subsidizing it as well. I know because some of my former colleagues are standing up a new ethanol plant. They wouldn't even try if the government subsidies weren't part of the deal. I've been helping them by finding technology to boost the efficiency of the corn starch to sugar step.
Ethanol is only a "viable" option because the taxpayer is subsidizing it as well. That's true for oil as well. The subsidies for oil are (understandably) much higher.
Remember Gulf War I? The war fought for the free flow of oil? Imagine that the US military had not fought that war, or fought the war and sent the bill to the oil companies?
Sometimes the subsidies we complain about are not as out in the open as we might imagine.