Natural gas is SH!T for fuel economy whether in buses or half-ton trucks. It's also not really as "clean" as has been sold to the public consciousness.
Natural gas, however, *can* be a source for hydrogen. So could coal, wind power, water power, solar power, biofuels, and so forth. Because it's elemental, abundant it is a good common denominator "fuel" because the potential sources are so varied and the more sources possible, the larger the fuel capacity we will have to use long-term. No more being held hostage by OPEN.
I take it you mean OPEC. Anyway, yeah, if we can generate electricity cheaply enough then we can make use of hydrogen from a lot of sources economically.
However, it's much cheaper to use natural gas as a fuel in ICE engines than to use it as a source for hydrogen, which is then used in vehicles. Natural gas is less energy dense than gasoline, that's true-- but so is hydrogen! And not by a small amount, either.