I am continually amazed at the angst it causes many people when you suggest that the current American way of life will have to change. When you say that in 20 years people won't be driving everywhere a lot of folks really freak out.
The arithmetic plainly indicates we simply will not all be driving or riding in cars regularly in the future. Hydrogen vs. lithium batteries vs. gasoline doesn't even enter into it. There simply won't be the joules for everyone to get about that way. People will be walking, bicycling, and riding boring old 19th century speed trains. Peak Oil is now-ish and nothing else is set to provide the joules necessary to power personal vehicles on the current scale, regardless of vehicle power plants.