I can clearly see a path in which the Bitcoin already mined will be used to secure the blockchain in a future proof of stake dialect, in a not so distant future. If the chain - and I mean Bitcoin - will stop minting tokens at 21 million, the actual functionality of the said chain must be supported by the staking of pre-existing Bitcoin.
You may have a point. Suppose the price of BTC goes up by 100x in the coming decade. We'd be looking at BTC at $1.8 million. Because the cost of mining one Bitcoin follows its market price, mining Bitcoin at a price level in the millions of dollars could prove an environmental disaster. Suppose the average cost of mining one Bitcoin were $1 million in 2029. That's two mining reward halvings from now. The annual issuance rate of BTC will be 1.5625 BTC per ten minutes, which is equal to 624365 = 82,125 BTC per year, which would be worth maybe $82 billion. The energy cost of mining Bitcoin is between 90% and 95% of the total. Let's say $72 billion.
https://www.investopedia.com/news/do-bitcoin-mining-energy-costs-influence-its-price/
At the same growth rate, the total electricity generation market would be worth $2,095 billion.
At $1 million dollars per BTC, the share of Bitcoin mining of the world's electricity generation would be about 3.45%. It's not an overwhelming proportion but it is quite a lot.
Thanks for running the numbers for me, I had just an intuition that at some point PoW will be obsoleted somehow, but the actual unfolding of events wasn't clear.
Your scenario has a lot of chances to realize. Might be other paths as well that will lead to some dialect of PoS on the Bitcoin chain, but energy cost is definitely very plausible.
3.45% of the global total in 2029 isn't the utter disaster I envisioned the power consumption of Bitcoin to be before looking at the numbers more closely. But it's pretty bad. I don't think, however, that Bitcoin will be anywhere near the first coins to adopt PoS. But you have an important point to make regarding PoS becoming more feasible when a large share of the total of the coins ever to be issued have already been issued.
At that point, we should be celebrating if one bitcoin was at 1 million dollars, huge win for the world lmao.
Anyways:
If at the high price, alot of wasted energy today would be converted to using mine bitcoin. So while alot of energy, it also won't be wasting much energy. POW after all is a way to convert energy into money.
POW is still a natural force distribution mechanism as miners have to sell their bitcoin to pay their bills after all while in POS we are keeping the coin more and more.
I argue POW for bitcoin at least would remain as kinda like a global standard.
Funny this argument is also at play that since bitcoin focus is offchain, there wouldn't be any money for miners thus miners will leave in waves thus also making POW bad. :P