Hydrogen in particular is very difficult to supply as a major fuel source. H atoms are always combined with other atoms in the universe, and separating them is very energy-consuming. This may be a regional thing, but for all the hype and whining I hear about global warming and the necessity of alternative fuels, Hummers and Chargers are selling just fine where I live. If people were genuinely, deeply concerned for the environment, manufacturers wouldn’t be able to sell fuel-inefficient and economically substandard cars. It just turns out that we don’t care as much as some like to think. It’s far easier for a plant to go on producing the same dinosaur-chewing technologies it’s been building for decades, so it simply isn’t fiscally sound to invest R&D into a car people don’t actually want.