Your figures for ethanol powered vehicles are a little off. I have a flexible fuel F-150 truck. It gets 22 miles to the gallon on 93 octane unleaded fuel at $2.96 per gallon and 20 miles to the gallon on E-85 fuel at $2.49 per gallon (My actual experience, yours may vary.)
Cost per gallon difference=18.6% less - Advantage E-85
Miles per gallon difference=9.1% more - Advantage 93 octane
Looks like a 2:1 return on investment to me.
Invalid comparison, please make a valid one before saying that my figures are off.
Don’t forget, you’re also paying taxes to subsidize ethanol production, so that E85 actaully cost more than what you paid at the pump.