There's no underground pool of gasoline either... Crude has to be refined...
That's not the point. The energy used to refine gasoline comes from the oil itself. Gasoline doesn't hold all the energy from the oil consumed to produce it, but it's still a positive net energy transfer from the well to your fuel tank.
Producing hydrogen, by any method, requires an external energy source. Unless someone figures out a way to get energy from the water used to produce hydrogen by electrolysis, hydrogen production is a net energy sink. The last time I checked, such an energy source (nuclear fusion) was still many many decades away. And has been many decades away for decades now.