I think it's functionally impossible for Bitcoin to hit literal zero. It could someday run on a network of ten hipster tech-history enthusiasts, worth micro-pen

I think it's functionally impossible for Bitcoin to hit literal zero. It could someday run on a network of ten hipster tech-history enthusiasts, worth micro-pennies like DOGE in the early days, but it still wouldn't hit zero. I agree that Proof of Work has a severe scaling problem; which is why I expect Proof of Stake to outcompete PoW (a token with lower transaction costs being inherently more desirable as a store of value). AFAICT PoS scales linearly: as the market cap goes up, the opportunity cost of locking tokens, and the mining rewards, both go up proportionally. It'll be interesting to see if BTC maxi culture sees the writing on the wall, or sticks to their guns to the bitter end; even if they're right that it's a better security model (I'm doubtful), it wouldn't be the first time that "good enough" won the market. I suppose the biggest reason that we'll never see PoW vanish completely, even if carbon-taxed or outlawed by most states, is the massive capital outlay in ASIC mining hardware, which literally has no other use. There'll always be a desire to recoup that investment, and an incentive to foster "true believers" to maintain demand.