In your opinion/experience, why is it that they aren't switching?

Probably a mix between oil-ties and the fact that decisions in Japan are made slowly.

Edit: I also think there's a fear of this: wide acceptance of EVs open the door to BYD (or similar) huge takeover of the car market.

I have a theory: Japanese car's have excellent reliability, their interiors and design are lacking. If every car in the world is an EV, which due to their relative simplicity tend to be reliable, what remaining unique selling points does eg a toyota have?