Technology

Hydrogen cannot supplant batteries in mass market cars. It doesn't make sense, primarily for reasons concerning the laws of physics.

It takes a tremendous amount more energy to power a hydrogen car.

Use a lot of electricity to split water into Hydrogen and Oxygen, force the oxygen to react with another substance leaving pure hydrogen, siphon it away, spend more energy compressing it to bomb-like pressures (or alternatively cooling it until it becomes a liquid, at great energy cost), transport it to hydrogen stations, pump it into cars, do reverse hydrolysis (also incurring a large energy loss) to turn it back into electricity to charge a battery to power an electric motor. [Bonus: since the battery is tiny, it can't supply a huge amount of power instantaneously - making hydrogen cars far slower than a typical EV.]

OR:

Take that electricity, send it over some wires with over 95% energy efficiency, charge a battery that powers an electric motor.

Then there's the safety considerations for the cars because they have highly compressed hydrogen on board, the same is true for hydrogen fueling stations which cost a fortune and have an unbelievable amount of red tape. Meanwhile it's easy and cheap to add charging points everywhere, because practically everywhere already has electricity.

Their range isn't even much better, because not only is the energy density really bad compared to petrol or diesel, you're also compromised on fuel tank size due to it having to be small, spherical, unlikely to be struck in a crash (ie must be put in an inconvenient place re: car packaging) and phenomenally structurally strong, all to prevent it from exploding like compressed hydrogen likes to do.

There's a reason why despite every manufacturer toying with hydrogen vehicles for decades, there's basically only the Mirai that you can actually buy, for an awful price, and it's a shit car, while there are several hundred EVs out there right now. One is a viable car technology, and one is basically an EV with a long list of compromises.

And Honda was working on hydrogen nearly 30 years ago now, which seems poised to suplant batteries (again, maybe).

LOL, no. Hydrogen has never been anything but a greenwashing scam. Even if it were all produced from electrolysis (and to be clear, it isn't -- the vast majority is produced from fossil fuels), it would still be stupidly cumbersome to deal with compared to adding some carbon to it to make synthetic gasoline.

Lol, hydrogen. A chronological oddity. Has spent the last 30+ years just 10 years away from being viable.