Car maker's attraction for fuel cells is that they neatly replace the internal combustion engine with another large, heavy, hot mechanism that continues to require about the same amount of ongoing maintenance. So the automaker's balance sheet remains about the same but now it's green.
As Musk pointed out some years ago, hydrogen is not so much a fuel as it is an energy storage medium. Right out of the gate creating the hydrogen reduces the system efficiency by about 50% because of the electricity required.
In essence then hydrogen fuel cells are just a less efficient form of electricity that require a complex and expensive mechanism to turn into motive force. Possibly useful for shipping or trains but not the way to bet for cars.