This is not true. Like any resource, gold tends to cost more to extract from the earth over time. As deposits diminish, we must look elsewhere and settle for go

This is not true. Like any resource, gold tends to cost more to extract from the earth over time. As deposits diminish, we must look elsewhere and settle for gold ore with fewer parts per million. This requires more expensive technology and newer techniques to be developed. Hence, it predictably will cost more to mine gold in the future than it does today.