The current global car market is about 70 million vehicles not 1...

The current global car market is about 70 million vehicles not 1 or 3 million vehicles. Then of course there's buses, trucks, tractors, ships, aircraft and potentially much larger markets outside of transport. If EV technology becomes mainstream as some car-makers are suggesting then the market could be very large indeed - there's no reason it couldn't be 90% or more if some technical limitations are overcome. If it remains a niche technology then there is still a demand shortfall that needs to be met, though the bigger issue is one of supply security. There are only a couple of major large suppliers and a large part of production is from China. This could potentially be withdrawn from the export market as has happened with many other minerals the Chinese have deemed as strategic.

The postings on various manufacturers moving to lithium are perfectly relevant imo. They indicate that the technology is indeed becoming mainstream and there are very few manufacturers who are not now designing an EV or hybrid. Almost all are designing around lithium battery technology. So quite possibly the market share will end up being at the higher end of the range. Either way car makers won't want to be taking any chances as a lot of money is being invested in R&D atm.

If you want to see how profitable this kind of company can be then have a look at SQM in Chile. Most of their earnings growth has been driven by potash recently but there's every chance lithium could be the real money spinner down the track. For the time being I can't think of any reason why fertilizer prices in Chile would be significantly different to those in Argentina.