Pure electric cars are never going to be a full fleet replacement. There's one big thing that many Americans do with their cars that the pure electrics simply can't pull off: cross country driving. To do cross country driving you need to be able to refill/recharge your car in 10 minutes or less, there doesn't seem to be anything on the horizon in battery technology that could pull this off. Electrics might be fine for the normal driving condition (though with the way commute times have been growing even that could become problematic), but most people aren't going to want to keep an extra car around just for summer vacation.
Then there's the problem of apartment buildings, especially down South. Plugging your car in overnight sounds great if where you park at home is within a a normal extension cord length of one of your outlets. But there are many places where home and your parking space are a good distance apart. Up North this might not be such a big deal since much of that territory has oil freezing weather and people need to plug their cars in overnight anyway (thus the necessary infrastructure is already in place for an outlet accessable to every residential parking space). But South of the snowline, which is where the US population is shifting to, probably less than half the residents could easily plug their cars in.
"To do cross country driving you need to be able to refill/recharge your car in 10 minutes or less, there doesn't seem to be anything on the horizon in battery technology that could pull this off."
Check out eestor. It may be vapor-ware but they are supposed to be delivering product this year. It is an ultracapacitor with battery like storage. Their big advantage is being an ultracapacitor, it can be charged as fast as you can throw current at it, they claim 500 mile range with 10 minute recharge.
I aggree with you about full fleet replacement. However, if Tesla's Roadster does what it claims it could fit a niche segment of the marketplace.
It is relatively expensive BUT so are all sportscars that go 0-60mph in 4 seconds with a top speed of 125mph. I could see alot of the rich liberals buying these.
There are alot of people that are pissed off enough at big oil and Middle Eastern types to buy something like this just to spite Exxon & the Saudis.
The Tesla is similar to a Mazda Miata or any other 3rd car(I own a Lexus SC400 coupe) that only gets driven during the summer.