I burn 10 gallons every 11-12 days. I have a 17 mile commute, 1 way.
Did it occur to you that many, many people might buy smaller commuter cars if they got 50 mpg and the fuel was naturally produced?
Did it occur to you that we might have a MIX of cars on the road, daily commuters going bio-diesel and weekend vehicles using petroleum?
Not every vehicle has to run on the same type of fuel.
You are trying to debate a mixture of bad math and bad logic. Trust me, i am not a fan of ethanol, but I don't see any proble with replacing some of the current petrodiesel use with biodiesel. It's currently being done profitably, too.
we do have 50 mpg cars on the road today - a lot of them hybrids. People just don't seem to like them. I average 17-20 mpg with the GT, and about the same with the Jeep. That isn't bad mileage (Jag gets between 4-8) considering. Most people I know drive further and burn more gas than I.
adn if you have a mix of different-fuel cars, then you'd have to have a mix of different-fuel gas stations to support them. Deisel cars didn't take over the market (like we were told) in part because the fuel delivery infrastructure isn't there. 30 years later it still isn't.
And deisel is far more common than exotic plant-based fuel is.