It's easy to say "we should convert to a hydrogen-based economy" or alcohol or whatever alternative you care to name. The hard part comes when you set beyond the "that'd be neat" phase and actually try to make it happen. This is where you separate the engineers and economists from the pipe dreamers.

Creating the infrastructure for a hydrogen, alcohol, or whatever-based transportation system will cost many billion dollars. Who will pay for it? It's also a chicken and egg kind of thing. Not many people are going to buy vehicles powered by alternative fuels until there are enough refueling stations, but there won't be very many refueling stations built until there's a market for their products. There's also the fact that over 100 million cars are already on the roads and will either need to be converted, scrapped, or provided with the fuel they were built to use.

The issue with freedom is a simple one - you, I, and certainly not the government don't have the right to dictate to others what they "need." Your needs almost certainly differ from mine. "One size fits all" is a lousy alternative regardless of whether you're talking about clothing, education, or transportation.