If you go to the source of that claim, you'll see that it's basically about proven reserves, using current tech and know how, basically how we did it for oil, w

If you go to the source of that claim, you'll see that it's basically about proven reserves, using current tech and know how, basically how we did it for oil, when we were supposed to run out of oil in 1872, 1919, 1960, etc. We've just started looking for the thing at the scales we need it now, prospecting and extracting and processing it will improve.