Food for thought on the whole lithium availability vs. cost issue.
There isn't much there.
The question asked if the cost would go down as its used more, and the answer to that is that as demand increases, the price will too. That was not answered in that link.
Additionally, there is the assertion that fossil fuels will run out, but that data comes from enviornmental radicals trying to generate a crisis in addition to the raw material folks actually getting it out of the ground at a set price. Again, if there is an impression of a crisis in supply, the price will go up. There has been research done that found that the earth potentially produces petroleum raw materials as a part of its natural process, not as a process of decayed, fossilized remains.