Bulldust
market forces drive the economy. If someone invented that miracle car, it would sell like hot cakes, IF it was reliable and affordable. Most proposed alternatives are not, or only work in a niche market (Refining used cooking oil into biodiesel was great proposition for the first few people doing it. Now used cooking oil has gone up in price and the deal only makes a small margin - and there are nasty wastes to dispose of)
The fact that the "miracle car" isn't out there is good evidence that there still isn't a better way to get mobile than the Infernal Combustion Engine, running on hydrocarbon fuel...