[WorldMaker]

Toyota is also probably stuck in a weird version of the sunk costs fallacy at this point, having spent R&D money continuously on hydrogen fuel cells and hydrogen fuel cell vehicles since the 1990s. Luckily for them, a good hydrogen fuel cell vehicle is just a good EV with a really weird "refillable battery", so their sunk costs aren't likely to sink the company because the rest of the "drive train" is the roughly the same for HFC and battery EV.

[AgloeDreams]

Exactly, they were originally acting extremely forward thinking. The one thing they simply did not see coming is the mid-2000's mobile tech revolution. The cost of lithium batteries fell like a rock to where they are today (due to smartphones, etc) and that was simply unforeseeable 20 years ago. What Toyota needs now is a single skateboard platform for both BEV and FCEV and then to simply build the FC models with a dummy pack structure and keep the entire rest of the design the same.

[WorldMaker]

To keep weight/handling similar they could probably even fill it with as many batteries as they can subtracting only the full weight of a filled fuel cell (ie, it may not be so much of a "dummy" pack). That might keep HFC EVs in line to be the last surviving PHEV model as ICE retires, which would keep/permanently enshrine Toyota's (Prius) spot in the PHEV hall of fame.