The i3's disjointed hood and gigantic bumper give the car a strange look that screams "I'M ELECTRIC!" the same way a Prius does, and the market for cars that scream "I'M ELECTRIC!" is already oversaturated.
Until car manufacturers can make an electric car that looks at least as normal as a civic, Americans will shy away. A huge part of the model 3's success is that not only does it look normal, it looks _good_.