Why Havent We Started Converting Things To Ethanol?

To fuel all motor cars in the world or a large amount, you would need mive amounts of ethanol, and seeing as ethanol comes from food crops, we will see food shortages and/or high prices on food. So would you rather using your car for transport, when you can use other alternatives like walking, riding a bike etc.? Or would you rather be paying through the nose for food, an item we cannot live without?