Lots of people already buy cars that are not the cheapest possible car. Sure, if electric vehicles were cheaper than an equivalent gas-powered car, then that would be awesome... but even if that isn't true yet, there are a lot of people who'd like an electric car anyway.

Estimating from the 400,000 Model 3 preorders, that group is in the low millions.

Meanwhile US auto sales are 1 million+ per month. The larger automakers are all working on electric platforms, they aren't ignoring the market that is there, or more importantly, the market that will exist as costs come down. But the point is that they don't really have much to gain from getting way out in front of the battery costs.

This just isn't true. The cost of ownership of a Model 3 vs even a Civic will save almost $2k/year.

Cost of ownership wise nothing will be cheaper. Check your facts.

So I'm wrong because a car shipping in volume in 12-18 months will be cheaper than a car I can buy right now?

I also wonder about the math. Edmunds puts a Civic at about $5000 a year (for 15,000 miles):

http://www.edmunds.com/honda/civic/2016/cost-to-own/

To save $2000 a year over that, a Model 3 has to go ~10 years with minimal costs beyond electricity.