This is due to the state of battery technology at this moment in time, which has generally remained unchanged for the past 100 years. This is changing though and fairly rapidly and mostly due to the California ZEV mandate. If there was no need for a better battery for an electric car that MUST be sold starting in 1998, the auto companies would not be working on this.
What we must do is to rearrange our thinking from 'how far CAN I go' to 'how far do I NEED to go'. If we can do this, the milage questions about EVs will disappear.
The future though does look promising.
The record for an EV with specially built, experimental ($$$) batteries is 450 miles on one charge.
Another vehicle just went 230 miles on one charge with batteries that are close to production and should be available at a resonable cost when they do come out. This vehicle was the Sunrise, a pre-production car built by Solectria. They expect the car to sell for around $20,000.00 in volume production.
Many battery technolgies cost a lot of money right now, but you've got to remember is that just like computers or any other item, if they are brand new or you only make a few of them they will be expensive, so mass production is the key to keeping the costs down. And the high prices to replace batteries that the anti-EV groups put out, are the one-off specialty batteries, not the mass produced types like lead acid or the near (future) term batteries that are being developed like the ones in the Sunrise.