Historically, lithium was not interesting to mine at scale until the invention of lithium batteries thirty years ago. And only about ten years ago we figured out that we needed a lot of lithium to power things like cars, trucks, planes and electricity grids.
We've only been looking for lithium for a relatively short amount of time. Before we started looking, it was a relatively low value by product of mining other stuff. There's this perception that we have to go to places like Bolivia, Australia, etc. because that's where the known, easy to access deposits are. But as this article shows, there are probably loads of other places that might have rich lithium deposits.
The market for refining lithium is basically expanding at the pace we can build refineries. It's apparently a big reason Tesla chose to build their own refinery in Texas because the rest of the industry was not moving quick enough. Supplying lithium to the refinery isn't the issue. There's plenty of it. And if you start looking, you'll find some more. Rich deposits like this are of course nice and rare. The high concentration of lithium means extracting it is relatively cheap. But you can get it out of ocean water, there are natural brines in various places that have it, clay and rock deposits all over the place. By mass, it's one of the more common elements on this planet.