That is certainly not the only reason why EVs are still so expensive. Raw materials for batteries are a large portion of their cost. Currently, the cost of many of these raw materials does not account for a living wage for miners or the impacts mining can have on miners and the surrounding environment, and still the raw materials cost is a large portion of the cost of the batteries. Sure, there could be some magic new battery chemistry that circumvents this issue, but it's unreasonable to expect that. The previous data showing drops in car battery prices could keep going down, sure, but it's more complicated than simply economics of scale.