The trouble with Hydorgen and Batteries is
They both require exotic materials.
The catalyst in a Fuel cell is Platinum or one or a combination of
exotic metals of which there isn't a large supply .
Of course Musk is looking at space mining.
With batteries we have Lithium which is also a somewhat rare material.
So there needs to be breakthroughs in these area's, as in find substitutes that are practical on a large scale .
It would be a nice dream to have personal Energy Independence on a large scale. Solar and Wind at your house and off the grid for the most part .