I think for lower-income buyers, the initial cost is prohibitive - even with long-term savings and benefits. And I'm guessing some banks would hesitate to give the extra loan money as well if you don't have the income to support it.
It is kind of like buying a decent pair of shoes. If you are working retail, it muchly benefits you to buy good shoes. But you have to save for those shoes because of income limitations: If your current shoes wear out before you can buy new ones, you get sucked further into a cycle of cheap new shoes.
It really doesn't matter if you get long-term benefits or have a great desire to be environmentally friendly if you can't afford to do so. I think once we have a decent used car market with them and the price comes down to soemthing on par with higher-emission vehicles, there will be a much larger change.
If you haven't noticed the hover-able version of the chart where you can see what each dot is, it's here: http://carboncounter.com/
I remember running the numbers and while I was walking to work and basically never driving keeping an ancient sub 25MPG in the city car was both much cheaper and actually better for the environment than buying a Prius. Note this was at ~1-3k miles driven per year.
So, my guess is it might have some small impact at the margins. But, mostly in convincing people to do something they where thinking of doing anyway.
It is also where you burn fossil fuels. This is why I'm so enthusiastic about Uber and Lyft in cities: The drivers have an incentive to use well-maintained vehicles instead of smoggy clunkers. If I can smell your exhaust, then you are doing something wrong.
The built environment also includes roads. Fuel-efficient cars pay less gas tax, and most are lighter than gas-guzzlers, but long-range electrics like the Teslas are monster road destroyers that pay nothing to road maintenance. I'm not arguing for fuel-wasting vehicles, though; I think people should be using cars far less. Congestion charge or something.
At the time I would go weeks without driving / riding in a car. This was really for weekend trips where Uber is not really an option or once a month going for heavy things like water I did not want to carry home. I looked into car sharing services, but at the time there was no good ones in my area.
But I was wondering what exactly you meant by "Teslas are monster road destroyers"? This is the first I've heard this sentiment. Do you mean that they are so heavy they do more damage than most cars, or just that they are not paying towards roadwork, thereby doing more net damage than gas vehicles?
Charging is an issue. However, I don't personally know any plug-in hybrid that is actually plugged in at night. They still get the government subsidies, and they can plug in at certain mall parking lots or appropriately equipped parking garages, but I think they're mostly driven as normal vehicles. That use brake pads and low-RPM gearing less than normal vehicles.
Also, unless GP lives in an area where those sorts of garages are available, at least in the near term, they won't have anywhere to charge, which seems a fair argument against purchase. For instance, I live in south-eastern Wisconsin, and while there are charging stations within driving distance, there aren't any that would be convenient on my way to or from work, and I couldn't simply leave it at one and walk to work (or bus, because we don't do public transit here).
Known costs are known, less of a risk. It's easy enough to buy a new EV car if the other factors here are resolved, but I don't think it's unfair to say too many issues are up in the air at this point.