Conclusion: mining is getting more and more pointless and that is happening in furious pace!
Mining cost of Gold in 500 to 600/ounce
I know, this is well-known misleading argument. Actually mining BTC is MUCH MORE ineffective.
https://digiconomist.net/bitcoin-mining-more-polluting-than-gold-miningAND ADDITIONALLY: reward for mining gold is not dropping in exponential rate.