I thought this was a decent read...
As 2018 Nissan Leaf arrives, data on US electric-car market offers reality check
What is it going to take to push the electric car forward in adoption? Currently less than 1% of overall sales if you just look at BEV, only 3.5 if you include hybrids and PHEV (thought it was higher than that.. but this article is not sourced.).
I know a lot of people say price, but it already seems to be competitive with ICE vehicles. Sure price will drive sales, but I don't think that is really the answer.
Battery technology? This could be a bigger deal. People will fixate on that 1%-5% use case where even if you have 250 mile range but needed to do 300-400 in a day? How long would the charge take? How available is it? (Infrastructure - probably also a big deal). How bad is the battery degradation and how do you deal with it? Maybe it is economics and a 200 mile battery costs less than $5k to replace?
Will it take a mandate (zero emissions) to get there?
Personally I think battery technology like solid state batteries or something that allows quick charging plus education and the car makers' desire to sell these cars all have to come together for it to really take off. Here is hoping that Toyota stays on track for its 2020 release of that technology. Ford seems to have lost interest... have not heard anything about the Model E in the last year and the Fusion seems stagnant in technology... no real electrification drive train changes since the model introduction. There are few sites guessing that Ford is still moving forward with a Prius competitor to be released in 2019... but there is no hype ahead of launch like there was from GM about the Bolt or Tesla for their model 3. My guess is that they are going to play it pretty conservatively and see where the market goes... play catch up if they need to.