I mean it’s just not generally energy efficient compared to batteries, and the majority of hydrogen tends to come about as a byproduct of, I think it’s propane and natural gas extraction and production. Electrolysis is pretty far off from being an effective competitor to batteries. I do still think that theoretically the specific energy is high enough that it doesn’t really matter, since that seems to be like the major limiting factor keeping electric from going mainstream, and me personally, I would probably also use the oxygen made by electrolysis for some cool rocket fuel cars, also cutting down on the lack of , but everyone’s against that because “The cars would explode you psycho/moron!” and other stupid idiot considerations that I don’t care about. But yeah, generally we don’t have enough of an energy excess to be able to run cars off of it in a reasonable way. Energy density still sucks also, but then, it’s not like modern cars tend to really use a lot of their space anyways, so I don’t think that matters too much.