Not true at all. Many cars had trouble running it in the 80s is why it went away then came back in this decade.
It didn't go away everywhere. We always had it in South Dakota.
Ethanol has done nothing but drive up the cost of corn, meat, and give the farmers some extra $$$ for corn crops. It produces less energy and gets poorer fuel mileage than non ethanol fuel. The extra fuel consumed means we still use the same amount of fossil fuel we always have. We just don't go as far on a tank.
E10 uses the ethanol instead of things like MTFE. It is used to put more O2 in the gas (read hydrocarbon reduction) along with more octane. E10 is not meant to try and replace our need for gasoline, it is only for emissions. The mixes greater than 10% are there to try and burn something besides gas.