“Big mistake IMHO.”
Maybe not. The cost of manufacturing things keeps coming down. The improved fuel economy outweighs the additional complexity of the hybrid power train. That’s my guess.
You can’t beat thermodynamics.
Not there yet, but there are economies of scale.
Just like the manual transmission. They are cheaper to make, but manufacturing actually cheaper overall to make all cars the same so manual transmission is now virtually a thing of the past in mass produced vehicles.
This will likely happen with Hybrids, but I don’t know if we are there yet, but clearly Toyota has decided we are going this route for this vehicle.