That was some kind of joke (he tweets on Ambien so the quality is pretty low.) People regularly accuse him of doing Bolivian coups for lithium or other things they just made up.
Note lithium isn't a rare earth element, it's actually pretty common but some sources are cheaper than others. As for Tesla, I believe they don't get lithium from Bolivia and have upcoming chemistries that don't use cobalt at all. Not sure about other EV or phone companies.