You are confusing loss of usable lead (or other mineral) with the concept of entropy. However, it is an important point you note that all recycling is not 100% efficient and eventually it will be uneconomic or otherwise not feasible to scrap off all the bits of lead that have been strewn about the globe in our growth.

The point I was getting at was that for oil the curve of production and the curve of consumption are the same. For lead the "consumption" curve is higher than the production curve because the lead can be consumed multiple times through recycling. By this mechanism it is theoretically possible to maintain or even increase consumption after production has peaked.