How was helium extracted to build those reserves in the first place? (Fractional distillation of liquid natural gas?) Is that simply not viable or cost effective anymore?
So it'll be running out of helium that will make it finally cost effective? /s
You're thinking of He3 isotopes. Standard He4 is a byproduct from natural gas extraction.
Helium has a lower condensation temperature than Natural Gas, so when they make liquid natural gas for shipping, they can take out some percentage of the helium relatively easily and more with difficulty.