I am not sure I understand the negative sum game you mention. The first payment miners get is (I don't know the proper name) a bounty, which is equivalent to a gold miner obtaining gold. This can be seen as a built-in inflation, which not only gold but also any fiat currency has. The difference is there is no known limit on this inflation factor for gold or fiat currencies. For gold we assume some gargantuan deposit will not be found and that it will maintain its scarcity. I don't think anyone thinks there is an inflation limit for the US dollar or any other fiat currency. Bitcoin has a known amount limit. (As a disclosure, I own gold, bitcoin, and US dollars.)
The other part of what miners make is a transaction payment. That exists in every other payment system I assume, except I guess physically handing an object to another person, which covers a pretty small fraction of transactions.
Now to be sure there are some customers of the bitcoin system, using bitcoin as an intermediary to move money across borders or purchase from certain online marketplaces, and those customers are paying some amount of money into the system to use bitcoin for this purpose (analogous to the 2% that VISA skims off the top when you use your card to buy something on Amazon), but the majority of the money flowing in to balance that $20B outflow is from investors buying in. Unless you think bitcoin has managed to capture something in the order of $20B/year in transaction fees from the likes of Western Union, AMEX and Paypal, what's mostly happening is money being funnelled from investors taken as a whole to the the supplier industries that bitcoin relies on.
I'm taking about examples like when someone uses bitcoin to transfer money, by converting an external currency into bitcoin, sending the bitcoin somewhere then converting it back into an external currency. Whatever loss of value they see from that overall transaction has been transferred into the bitcoin system as a whole.
Except that it is impossible ever shut down Bitcoin mining at once(). It might be more similar to gold than what you think.
There are too many incentives to keep it up. The holders want value to be kept, the miners have vested interest in the system to continue to work. If you shut down, say, half the miners, this will create opportunity to other miners to invest and expand. If it drops too much, people inject money into the system, which gives liquidity to the miners again, that can continue to trade their work for goods and services with Bitcoin or by trading Bitcoin for fiat.
It is very similar to Visa, Mastercard, Stripe, Square and other centralized systems. The fees you pay for transactions keep the centralized finance business working and profitable as well as they invest back in software and hardware. For miners the Bitcoin fees, based on Bitcoin price, keep their systems profitable too. Not to mention some mining companies started to get listed on the stock market too.
(): Yes, you can shut down Bitcoin eventually, bugs, attacks, etc., but those have been tried and not very relevant to my point.
For those unfamiliar, Beanie Babies were a collectible toy that had a multi-year fad in the 1990s, with 5-dollar toys trading for thousands: https://www.ft.com/content/1563d643-332f-3887-8c6e-caf7435f3...
It's true that the Beanie Baby market never totally went away. And I'm sure that some die-hards will keep Bitcoin going for decades after it ceases to be practically relevant. But however much the bubble incentives keep major players aligned during the bubble, that doesn't mean the prices will stay up forever.
I wonder if we'll see things like that in the NFT market.
This is not really true--it's not like lowering the security budget means all the old blocks can be rewritten at will. Roughly speaking, the cost of rewriting a block is the cumulative PoW cost of that block and all the blocks after it, although this amount typically decreases over time as better mining equipment lowers the present cost of hashrate.
For current transactions, if the security budget relative to the transacted value gets low, all it means is that one must wait longer to achieve the same level of confidence in transaction finality. It doesn't abruptly render the currency "utterly worthless".
The difference is that if you shut down gold mining, existing gold would still retain all its value. If you were unable to protect your gold reserves, they still retain all their value. If you shut down Bitcoin mining it's immediately worth nothing. In fact if you reduce your energy expenditure below some unspecified threshold it becomes utterly worthless. Mining gold consumes resources, but once extracted it does not. I would consider it to be zero-sum, as compared to the negative-sum nature of Bitcoin.
I would argue if institutional demand and even jewelry demand for gold fell, it would still be a fairly valuable commodity, and its use in electronics would likely expand substantially as it became less expensive. Connectors, switches, wires, PCB contact plating. All big demand drivers, and gold is better than the status quo - just too expensive at the moment.