Hydrogen source, transport, and filling stations will never happen on a scale they are needed. From here:
API | Service Station FAQs "as of 2/28/2014 there were 152,995 locations nationwide selling gasoline, including service stations, truck stops, convenience stores and marinas." So, let's say there are ~150,000 gas stations for vehicles. On average, I think each services ~25 vehicles a day?
That's as much as 3.75 million fillups per day.
Typical hydrogen filling stations can service just 15 vehicles per day, so that means we would need ~250,000 hydrogen filling stations. They each cost ~$2M.
That is $500,000,000,000 for the filling stations alone.
If we could build TEN PER DAY, 365 days a year - we would be finished building them by 2085.