If we get into an actual shooting war with China, I don't think there's enough hydrogen generating facilities to make much of a difference. If maybe 20% of vehicles on the road were using hydrogen, maybe?

Considering how much money and effort both Toyota and Honda have poured into trying to kick start a hydrogen economy over the past decade and a half, and how much EV technology was evolved over the same time span, would it not make more sense to switch to the technology that actually is proven and actually has consumer demand for?

It's not like they're switching all that military hardware to hydrogen too.

Japan can't solve all of its energy woes, but it can ease it a lot by restarting all the nuclear reactors they shut down after Fukushima, and to be fair, they've been trying [0], but stuff breaks after not having been used in over a decade.

[0]: https://www.bbc.com/news/articles/cq6v0v32rg1o