Notice that the same page says that the Earth's crust contains 20 parts per million of lithium. That's more abundant than tin or lead, to name two rarer elements that are currently mined in much larger quantities:

https://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth...

Here's the USGS lithium report from 2010 that this Stanford web page got lithium reserve and resource numbers from: https://s3-us-west-2.amazonaws.com/prd-wret/assets/palladium...

Here's the corresponding USGS lithium report from this year: https://pubs.usgs.gov/periodicals/mcs2022/mcs2022-lithium.pd...

See the tables "World Mine Production and Reserves" in these reports and following paragraphs.

From the 2010 report to the current report, world lithium resources went up from 25.5 million tons to 89 million tons even as extraction rates rose from 18,000 tons per year to 100,000 tons per year. That alone brings us up to 37 billion Nissan Leafs.

How can resources go up even as we're using lithium faster? It's because reserves and resources are determined by a combination of economics and technology. The Earth's crust contains 20 ppm of lithium now and 12 years ago (or a million years ago, for that matter). The geology doesn't change but the effort put into identifying potential sources of lithium and means of extracting and purifying lithium does change. Geologically speaking, the Earth has a lot of lithium. For as long as the USGS has been keeping records -- only a few decades, admittedly -- world lithium reserves have been increasing faster than they have been depleted, because the industrial demand that causes reserve depletion also spurs additional research to identify potential lithium sources and extraction processes. This Economist article is about such new processes.