Technology implementation very rarely follows a predictable path. As depicted in the old PBS series Connections, there is often a delay of centuries between the suggestion that something might be possible and its realization, and the results of an idea are often most prominent in a completely unrelated field. So we shouldn't be surprised if the path to a hydrogen economy is anything but straight. The real world is not linear, in either the mathematical or geometrical sense. When you (because I probably won't be here to see it) look around to see a world running on hydrogen, you'll wonder why it took so long.