You pretty much said it yourself... besides Tesla, everyone avoids other electrics.
Tesla's the only one who's done it right so far with the S and X and it remains to be seen whether the 3 is going to be a success. Sure, it's technically a success already with all the pre-orders and whatnot but those are the early adopters.
Here's a great image that explains why I think we've got a long road for electric cars:
At this point in time, we've barely eclipsed the innovators stage and hit the early adopters... once the Model 3 hits I imagine we'll get close to the early majority stage, but not enough to cross over.
Then you also have the underlined. For some reason, people think Tesla = luxury car so your neighbor Joe Dirt isn't going to bother looking at Teslas(it doesn't help that you can't just walk in to a Tesla dealership here in Texas for example). Obviously the Model 3 hopes to change that thought, but the car isn't even out yet so it's hard to judge whether the 3 can change that.
That said, I'm not against electrics... I know it's the future and I'd actually love a Model 3 as a daily driver since I have a long ass commute but at the same time I'm not willing to wait until 2018 or 19 for one. I just think that it's a little short sighted to believe that we'll all be driving electrics in 5 years... 10 years at the earliest IMO.
Also, I personally don't think the incumbents can figure it out ASAP. But like I said, we've got a long road before the electric revolution begins. I think once gas stations have been replaced by superchargers or whatever equivalent then I think the revolution can start. But at this point time, it's tough to convince Joe Dirt to get an electric since you yourself have to build your life around it.
