Concerning the cost of batteries and EV, it not just economy of scale. LFP batteries will lower cost chemistry quickly grabbed 50% market share. Tesla has designed out rare earth metals in their motors and excepts the manufacturing cost to drop by $1000. There are battery chemistries that have demonstrated 4X increase in range with a technic path to still higher energy density.
These advances are only loosely tied to volume. That is technology advances can be, likely will be disruptive for EV.
Battery technology with 100 year life for grid storage and low cost solutions like iron will drive down prices faster then volume alone.