It's key to understand that hydrogen in this context is merely an energy storage system (this is primarily for others RLK - you "get" this). It is not an energy source. You can't go out and drill for hydrogen.
Petroleum, on the other hand, is both an energy source and an energy storage system.
Now, who in Hades is going to start producing hydrogen from oil shales or coal or natural gas, when any number of petroleum producers can undercut them immediately? If the economics had a chance to work for something like this, people that don't depend on a far-flung distribution system (gas stations), like urban delivery vehicles, metro buses, etc, would be doing it. But the economics don't work, largely due to the lack of a competitive cost for an energy source.