The existence of a group of insiders runing the scheme is really a detail when it comes to understanding how the market works. If it works like a ponzi scheme, does it really make a difference for the victims whether or not some people get arrested?
There's ontologically, in the manner of pedants, where you're really asking "in this defined ontology of financial phenomena, schemes and frauds, where does Bitcoin fit in?"
There's descriptively, where you are asking if it is useful to model or think of Bitcoin as a Ponzi scheme, regardless of whether it is a fully accurate categorization.
And there's rhetorically, where you are really just using "Ponzi scheme" as a concise way to tell people, "Don't invest in it, people are trying to take advantage of you."
Have you heard about the miracle of decentralization? :)
Just to put some additional data to this:
Jewellery: 92,947 tonnes, 47.0%
Private investment: 42,619 tonnes, 21.6%
Official Holdings: 33,919 tonnes, 17.2%
Other: 28,090 tonnes, 14.2%
Below ground reserves: 54,000 tonnes
Since BTC has no underlying asset, it's hard to demonstrate a correlation with anything. So if you buy btc as a hedge, you could pretend you're hedging against anything. In reality, the only significant factor is btc's popularity.
That means you could probably buy anything that isn't correlated with Euro and get the same result.
We used to all rely on bonds and bills to stabilize our portfolios but central banks have killed that.
Gold is a scheme (not quite a ponzi scheme) in which we've all agreed to maintain the delusion that it's a good marker for totting up wealth. It happens to have nice material properties for that, and it's nearly unique in those properties. The main one being that you can't print more of it.
BTC has a lot of those properties... as does Doge, as does Ethereum, as does Bitcoin Cash, and every other cryptocurrency. BTC has the name recognition -- which it shares with gold -- and in doing so may or may not become Gold 2.0.
But once we've realized that there can be Gold 2.0, why not Gold 3.0, 4.0, etc.? Only gold can ever be gold 1.0. Even adding silver and platinum and such doesn't really substantially diminish that uniqueness. Whereas there's no one crypto... which means that the "you can't print more of it" goes away. The Dogecoin guy did it. So do thousands of others, every day.
Maybe BTC will become the one and only Gold 2.0 and it'll stop there, and if so it'll have a value of some sort -- hard to say what, but eventually it'll reach some kind of equilibrium. Until it reaches that point, it has only its hope to be The crypto, and for the moment that relies on a continuous flow of new investors.
Some original guy got rich by convincing others to take his lump of metal in exchange for goods and services. The fact that it's nice to look at helped. That happened thousands of years ago, and so we're all just living with it as a collective agreement. We could break it if we wanted to, but there's not much motivation to.
So that part of the D&D economy actually works pretty well; copper, on the other hand, is something like 3600x more common than gold.
If I understand the tweets correctly, Taleb, et al, are basically saying that the mining pool functions as the insiders in a Ponzi scheme, by outcome if not intent.
The argument is that a Ponzi scheme isn't just zero-sum speculation, with some people winning and some people losing: it is negative-sum, for the speculators, because the insiders were siphoning off money the entire time.
In this situation, the siphoning comes in the form -- among other things -- of the 6.25 BTC / 10 minute block rewards [$20B / year at present], which the miners sell to pay their costs [$10B / year of electricity at present?] and their own paydays. Because these "insiders" have been taking out money the entire time, when all of the investors go to get their money back, there won't be anywhere near as much money as they put in left to get out.