There are a lot of reasons to end the ethanol.
The one you listed wouldn’t make the Top 20 list.
Cars aren’t the only thing using gas. Millions of small engines are in use and almost none of them are ready for ethanol. A friend landed at an airport in his Super Cub and the gas pumps were broken. His airplane is rated for pump gas so he got some from town and dumped it in and flew on home. The floats in his fuel gauges were dissolved by the ethanol and dyed the sight glasses reddish pink. Our ‘94 Buick would barely run on ethanol, it would chug and slow over and over. Sure a new vehicle can take it, but an old chainsaw can’t. Or boat. Or car. Or truck. Or plane. Or tractor. Or generator. Or pump. Or.......
Here are some things it can do, none desirable.
http://www.popularmechanics.com/cars/alternative-fuel/biofuels/e15-gasoline-damage-engine-2