Like any new technology the initial development, research is costly....but in the long run, since the hydrogen may be obtained from natural gas, methanol or petroleum. It will be likely.....natural gas and methanol (even garbage) that is "going to waste" now will have value and will not have to be pumped or shipped from the other side of the world....
The cost will be in the process, not in the transportation, or raw product. That process will decrease in cost in time....
The other issue is efficiency, and I don't refer to mechanical efficiency but cost. Looking at efficiency from beginning to end it seems that hydrogen has to cost more than oil/gas to our transportation fleet. And it is so. But, somebody is looking ahead and seeing that oil/gasoline will not always be sufficiently available or cheap as it is now. That equation will give different results than it does now. Those who are complaining about the efficiency of a hydrogen economy will hopefully see the light--that mechanical efficiency is important, but not necessarily the determining factor.