So how does the Prius fit into this? How could Toyota have spent any money at all on electric technology when they had billions invested in gasoline combustion?

So how does the Prius fit into this? How could Toyota have spent any money at all on electric technology when they had billions invested in gasoline combustion? How did GM spend any money on their EV-1 when they were similarly rooted? There is a difference here with Tesla, but what you're saying amounts to a sunk cost fallacy.