it also means the fixed cost is higher because you have more volume of product necessary to create the finished product.
Until we get serious about genetically altered plants, so they have large amounts of sugar and yeast growing in the plant together, so a simply production process can start the reaction to create ethanol, we will not have cost effective ethanol. The math simply does not work.
It is always easy to point to someone else and say "you should do more" but we are literally up against the laws of mathematics on this.
So we go back to the issue, enviromental gains, or economic gains... unfortunately we have to make a choice....