No. People still prefer larger, sportier gas guzzlers. When those "smart cars" get into accidents with larger vehicles, insurers will greatly increase premiums making them less attractive.
I parked my 06 Civic next to a Mini at the dealership nearby. The Mini: costs more gets the same MPG is much smaller in case of accidents is relatively ugly doesn't have the legendary reliability and resale value of Civics has way less room and trunk space So why are people buying these roller skates? I have passed too many crash sites to have any desire to drive a 4 wheel motorcycle.