I am one of the biggest Tesla fanboys out. Everything Geoff said is true but he makes it seem like this is around the corner and it isn't even close. At least 60M cars are produced annually[0] and there are about 1B currently in the world[1]. A best case for tesla is to grow from ~50K cars to ~500K cars anually by 2020. There isn't an industrial base yet.

Some other manufacturers will contribute of course, but even if 60m electric cars rolled out annually starting now and started replacing ICE cars, that will take (1B/60M) * years, which is 16years and 8months.

The only way this could be sped up would be the rise of self-driving cars, an increase in public transport and the continuation of urbanization. If many manufacturers stopped making ICE cars and we used much less of them we could replace enough of the current fleet for it to be non-trivial in a few decades.

[0]http://www.worldometers.info/cars/ [1]http://www.huffingtonpost.ca/2011/08/23/car-population_n_934...