I mean literally extracting resources: mining, logging, fishing, oil extraction. As resources become more scarce, the market system causes the price to shoot up, incentivizing the completion of the process to extinction. In the case of cryptocurrencies, it's abstracted somewhat since we use electricity, but those energy resources must come from somewhere, and right now it's not renewables for the most part.

I get what you're saying, but the entire idea of bitcoin is literally an exponential ramp. Each new technology that improves speed (CPU->GPU->ASIC) will be a linear step up, but mining will get exponentially harder. There are network effects from the banking world, but I don't think they should grow even as (N^2 where everyone is connected to everyone else) as they probably use something between than and a spoke and hub model.