It would be more accurate to say that you won't accept an electric car until it can travel between 300 and 400 miles on a charge. That is a fair statement.

However its unclear yet that "widespread acceptance" requires that. The Volt and the Leaf are out there, so its really going from theoretical to empirical. After they they have been in full production for a year, if they (and the other electric vehicles) are not gaining market share commensurate with the vehicle replacement rate, then you can say "See they just don't have widespread acceptance."