[_aavaa_]

Forget the type of electrolyzer, even if they were free hydrogen would still be expensive. The challenges with hydrogen getting cheaper are thermodynamic and can’t be innovated around. The amount of energy required to electrolyze water simply cannot drop by 10x.

The other difficulties (low energy density, ability to leak through many materials, massive explosion risks, near-invisible flames, etc., etc.) are all inherent to H2 as a molecule.