There's actually been a lot of research into this for PV that probably applies to EVs too.

After initial government support from western nations mostly it's been economies of scale and innovation that have dropped the price of PV.

Prices that have been called dumping (i.e. sold cheaper than they sell in the home market, which harms the foreign manufacturers in an unfair way) have repeatedly been further beaten by the next generation of panel.

I expect to see similar with batteries, the main component by cost of EVs.