Zacs...of course there already all-electric cars, but as long as they have a range of about 100-150 miles, they will be next to useless for anything other than popping down to Sainsburys.
There is also the massive cost of replacing the batteries when their natural life is up.
In addition, they make next to no noise and are a danger to pedestrians.
Charging is also a major problem for most people, unless they have a driveway or garage to park in, and millions or people don't relying on on-street parking. If I were to use a Nissan Leaf to go to my caravan in Cornwall, the journey would take many hours, instead of the 3.5 hours it takes at present, and that is presuming that I could find somewhere to charge on the way.
Hybrids would seem to be the way to go in the future, although I will predict many millions of ordinary cars will be on our roads for decades into the future.