The fuel consumption of a Toyota 'Pious' is easily exceeded by comparable diesel cars.
The inherent fuel inefficiency of the petrol engine means that the attractive theory is simply not delivered.
The same problem afflects all batteries. After over 100 years of development we have batteries which are significantly lighter and have a higher power density than any imagined at the beginning of the 20th century. Compared with liquid fuelled internal combustion engines it is however still rubbish..............
Basic physics will out.
Dreaming about fission / fusion is also something of a pipedream, yes huge energy densities - until you start to add up all the supporting systems which are necessary to keep it together and stop it taking out a small city. The smallest practical fission reactors are probably in submarines - typically about 2,000 tonnes of 'stuff'.
Suitcase reactors? Not going to happen apart from a military reactor where 'collatoral' damage is irrelevant.
Cann't wait for electric aircraft? Even if you could do a 'Rip van Winkle' at the present rate of progress an electric sailplane is about the best you can expect.
Try flying behind a modern engine and you'll quickly see how pointless an electric aircraft is!