The point I was making was precisely regarding what is considered "valid" demand. Here, the fact that you appended "economic" after it strongly suggests to me t

The point I was making was precisely regarding what is considered "valid" demand. Here, the fact that you appended "economic" after it strongly suggests to me that we don't have the same definition of it. One of the underlying assumptions of all mainstream economic theories since the XIXe century is that EVERYTHING that comes from nature is infinite and has been provided to us for free, whether it's resources, clean air, a durably nice temperature, animals etc. What has a cost is to pay people and machines to extract those things, but not the things in the first place. Based on this assumption, we've acted as if nature was infinite and increased our rate of extraction to ridiculous heights, reaching the limits of a system that is sadly, due to the laws of physics, finite. One example : China has used in 3 years roughly as much sand for construction as the US has in the entire XXth century (btw sand is the new gold and a huge black market for it is now in place...)