I think a few people were expecting the same cost curves that happened with batteries to happen with hydrogen but it seems the challenges are more difficult to overcome. Otherwise I think a Solar PV plant combined with Captive hydrogen production for refuelling on major highways sounds interesting, at least in countries like US, Australia etc. I believe this is not just about PEM or AEM electrolyser or specific tech, it never got the scaling boost.
Ironically the stack comprising fuel cells of different types is possibly very well studied since decades.
For me the Wells to wheel efficiency never made hydrogen worthwhile for short to medium distances and this battle is effectively over.
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.