Try and find out the cost per KG for hydrogen, it's almost impossible. If you lease a hydrogen car, the fuel is included in the lease, and I've found it very hard to find a retail price for the stuff, but every price I have seen indicates it's phenomenally expensive, meaning a hydrogen vehicle is more expensive to run than a petrol vehicle.

https://www.hydrogeninsight.com/transport/analysis-it-is-now-almost-14-times-more-expensive-to-drive-a-toyota-hydrogen-car-in-california-than-a-comparable-tesla-ev/2-1-1519315

Here's some actual numbers, $200 usd to fill a Mirai, which will give you about 600km of range.

As to the battery swap thing, it took decades, and an EU ultimatum, for everyone to agree on a charging standard, what do you think your chances are of everyone agreeing on a battery design?

[–] Dave 2 points 9 months ago

The truck companies I've seen doing hydrogen are generating the hydrogen themselves with water and electricity. I'm not sure whether it's financially viable or not, they seem to be doing it for the reduced carbon emmisions.

And yeah, you're right, a common battery standard will probably only exist if say GM or some group of Japanese car companies uses a standard across all their brands and allows this to be used by others. In other words, chances are probably pretty slim.