Besides that, it's not all about fuel costs. Electric vehicles are fun, and generally low-maintenance.
So long as screwing people too poor to justify a new or new-ish car is politically unacceptable there will be some resistance.
Cars from the early '00s are still on the road. It's gonna take another ~20yr for the fleet to turn over organically.
I suspect that gas stations will start swapping pumps for chargers, and that will motivate people to switch too.
By the time this all happens though we will have more car sharing programs and maybe autonomous vehicles, so the ownership paradigm will be different in 2030 compared to now. Why buy a car that sits idle for 90% of the day?
This may happen some places, but I expect the charging infrastructure to ultimately look very different from the refueling one we have today. Today's fueling infrastructure is the way it is largely due to the difficulties of storing and pumping fuel safely (physically and environmentally speaking). There's no reason that an electric car shouldn't be able to 'refuel' at a restaurant, grocery store, or at work (ie, where we see most charging places pop up).
Having four-corners real estate and employees dedicated for electric charging all over even city is just inefficient.
Sadly, that (admittedly sound and good) argument will run headlong into the resounding cry of 'for the environment'. Since both sides of that fight vote for the same party (in the US) the option that brings more revenue into the government coffers is likely to win. See every fuel tax increase in the last 40 years in blue states as examples.
The obvious solution to this is to use the money from the carbon tax to fund a dividend that goes to everybody. Then the net result is progressive because everybody receives the same amount back but people with less money tend to buy higher fuel economy vehicles or take mass transit.