Say Lithium becomes essentially free because we find so much of it…would that drastically lower battery costs? Is our current supply of lithium limiting production?
As proof of that there are sodium-ion batteries on the market right now, but they're not price-competetive yet[0] despite using largely the same infrastructure.
[0] The potential is there though as they have an important advantage: you can safely discharge a sodium-ion battery to 0V for storage/transportation.