How long till these types of vehicles represent more then 1% of fleet?
Well the Powertrain in the car is compromised of small lithium ion battery cells. The point of the gigafactory is to scale the manufacturing of these batteries and reduce costs of LI-ion batteries. Car companies don't usually publish the cost to produce their batteries but various industry people seem to think the # is around 250-300/kWh. They wanna get it down to around 150 and eventually 100. Just 6-7 years ago it was over 1000 so the improvements have come fast. At 60kWh battery pack you can put the Powertrain in for 9k, 5 years ago that was probably 50k.
Below 200kWh and you should be able to make EVs that are on par cost wise with Internal Combustion Engines.
Their stated goal is 500k by 2020. We'll say 350k of that is in the US. That is 4% of the new car market and that is just Tesla. Nissan, Chevy, BMW, GM all will start producing more EVs if/when Tesla is successful. They just need an upstart to kick them in the ass to innovate. New product innovation in the car business is really capital intensive. Big reason they are the first new US car company in almost 100 years.
Obviously with fuel prices higher in other parts of the world like Europe/Japan/China, they might be able to sell faster there.