I don't need to see the end result to make the claim - the doomsayers miss the basic economic principle about incentives changing with prices. They extrapolate

I don't need to see the end result to make the claim - the doomsayers miss the basic economic principle about incentives changing with prices. They extrapolate trend lines out without realizing that every time something starts to "run out" people change their behavior in a way to either reduce demand, increase supply, or find alternatives. This happens time and time again. Oil is the most obvious example, but helium fulfills this pattern as well, and was worsened by the government meddling in the supply, effectively destroying the private industry generations ago. Despite that, and helium being non-renewable without many alternatives, I'm still confident we won't run out without needing to dive into supply and demand numbers.