Peoples choice is guided by what they percieve they will use the car for. So you buy a minivan if you have children, because there will be situations where you need the space, if you have more than 2 children that makes sense. And as you mention, you buy it for the two roadtrips. I know people who spend a crapton on an station wagon two classes larger "because they need to move shit every now and then", completly ignoring that if they just choose the car that fit their every day needs, they can rent the car they need for special occasions and come our way ahead financially.
Many people own 2 cars as well, and it just makes sense to at least make one of them an electric. That is in my opinion will be the tipping point where there is enough demand to heavily invest in proper charging network.
Yet while all 3 of my vehicles (2 cars and a motorcycle) are 2-seaters, virtually all of my driving is solo (and I'm not even talking about commuting -- I'm primarily a bicycle commuter. Okay, my other 3 vehicles have 1 seat and 2 pedals).
The "average" or typical use case is not how people choose their vehicle. They choose it based on the uncommon use case. The executive buys himself a Porsche not because it will get him anywhere any faster, or because she really knows how to drive it, but because it projects an image of what she could do. The SUV is sold on the promise of rugged camping trips and dodging boulders to transport the children safely back home under conditions that can best be described as "apocalypse". Hell, I have many car enthusiast friends who have bought practical, boring cars because they've got that 3rd row seating for hauling their kids' friends.... before they even have kids!
For 99% of use cases, yes, the electric car is cheaper and more convenient. But my next car will be a comfortable, powerful, gas-powered car with AWD. Why? Because today's weight (and efficiency) penalty for AWD is basically zero, and on the one trip to Tahoe a year where chain control is in effect, I won't have to freeze my digits off trying to fit chains (or, worse, get taken out by a vehicle careening out of control in the snow).. and I won't have to hunt down nonexistent charging infrastructure where I don't have a driveway, let alone a garage. It will be for the 2 roadtrips I take a year. It will be because, while the electric car is better for MOST of my driving, it doesn't accommodate the rare circumstances we really buy vehicles for -- Because the electric car isn't enough better at the 99% of use cases to make up for its virtual uselessness at the 1%.
I love electric cars. I've driven the i3, various hybrids, and the Tesla Roadster and Model S. Some day I will own an electric car, but I wouldn't surprise if the tipping point takes quite a bit longer to trigger than he expects.