if those reserves were economically viable to extract, they would be already being extracted.

Like this? https://www.thinkgeoenergy.com/vulcan-energy-achieves-drilli...

Economic viability depends on many things, lithium prices have been pretty volatile in the past, battery production in Europe as customers are just scaling up.

Everything depends on demand. Much of US shale oil hasn’t been economical to extract at times in the past decade. If oil drops below $60 most of the newer basins are not profit making. If oil demand (or OPEC) pushes oil below $35 the rest of US oil isn’t economical.

Prices change.