I think it is safe to assume that Toyota has irons in the fire despite the past bets on hydrogen and hybrids.  I'm sure that they've had some board members reminding their CEO of the challenges Sony went through with Betamax (vs. VHS). When the whole world is going electric it's best to get on board and indeed Toyota seems to be moving forward in that direction. 

https://amp.theguardian.com/business/2023/jul/04/toyota-claims-battery-breakthrough-electric-cars

I'm guessing we all have our fingers crossed that ELVA is involved with Toyota's SS effort in some way.