I have always thought that the long term future for energy and transportation was thorium fueled nuclear reactors running at full power 24/7 and any time they were producing more power than needed for the power grid, they would be producing hydrogen. Hydrogen is the low pollution ideal fuel for cars and thorium is the ideal safe fuel for nuclear reactors, see here, The Thorium Dream by Alex Pasternack .
The Toyota Mirai is a hydrogen fuel cell car. I have always been partial to hydrogen internal combustion (IC) cars, primarily because I understand internal combustion, I don’t understand fuel cells. We already have natural gas powered IC cars, which would run just as easily on hydrogen.
The big problem with all these new technology cars of course is the infrastructure to support them. Needed are the mechanics and repair shops equipped to service them and the big one, refueling stations. I have yet to see a hydrogen refueling station. At least with hybrids they can be refueled anywhere and plug in electric cars, well just plug them in at home.
Personally, my attitude toward all these high technology high mileage cars is, if I could afford one why would I care? Unless I just wanted to make myself feel good about being environmentally friendly. You would have to drive thousands and thousands of miles every year for the fuel savings to justify the cost of these new cars.
Realistically though, I think the future will see a multitude of different types of cars and fuels. The days of the gasoline cars dominating the markets are over. I expect gas and diesel cars will be around for a long time. But the hybrids, plugin electric, battery power, fuel cells, natural gas, hydrogen and whatever else new technology comes along, will be taking a bigger and bigger slice of the automotive pie.
Even some of the old technologies may come back and make a serious contribution to the energy / transportation equation. If the steam car enthusiasts have their way, it just might happen, Modern Steam Power, read here.
Across the taxiway at an airport where I used to work, was a group of mechanics restoring the old muscle cars in their hangar. At various times they would be working on Mustangs, Chargers, Corvettes, etc. Ocasionaly they would test one out by accelerating down the taxiway at full power, with tires screaming and motor thundering. The acceleration and wonderful noise would give you goose bumps. I would always comment to anyone who could hear me; Can’t Do That In A Prius! Those were the days.