> What I find interesting is the chart where they estimate daily mining revenue to be on the order of $10 million/day, assuming current prices. Probably, that computation should be easy to verify using the various Bitcoin websites.

One thing I like to point out is that right now mining is over-subsidized by the basic protocol: why is the block reward 25btc (or whatever it is now)? It's completely arbitrary and is paying the miners more than their services are worth (hence the arms race to earn as much of the reward as possible).

The point of mining is to secure the blockchain and render it infeasible to perform double-spends, right? But double-spends are not that disastrous: a few double-spends are an inconvenience and not a disaster for Bitcoin. There is no need to allocate 25btc a block to achieve the current record of close to zero successful double-spends. It is wasteful.

So as the block reward declines, we'll see more reasonable amounts of revenue flowing to miners and hence also a decline in how much computing power (electricity) is spent, eventually converging on what is optimal for securing the blockchain.

So... you'll have miners who have sunk huge investments into powerful computers who are unhappy to see their investments become worthless, and who have the computer power to force high transaction fees onto Bitcoin users. That'll certainly be interesting to watch.

Somebody is going to lose big time. The question is whether Bitcoin as a currency will survive in the fallout.

The decline in block reward is gradual and predictable enough that your scenario simply won't happen.

double-spends are not that disastrous? You've go to be out of your mind. If your bank or credit card allowed you to double spend your account they would be out of business very very quickly. Same thing applies to cryptocurrencies.

Are you sure you understand how double-spends in Bitcoin work? If you did, the right response would not be to double-down and engage in false dichotomies where a single double-spend of any transaction ever is a 100% disaster, and instead, adopt the more nuanced perspective that a few double-spends will not kill the currency, will save vast amounts of computational resources, and users can opt into however much security they require by waiting an appropriate number of confirmations.

$3000 million is certainly a lot less than the cost of a military powerful enough to defend such a centralized system from government takeover. Also, I think the right comparison is not a hypothetical single server handling transactions, but the current bloated global financial industry. I'll bet $3000 million doesn't even cover the air conditioning bills for the offices of the financial institutions whose jobs would be better handled by Bitcoin.

As for the military: That may well be true, but who is willing to spend that kind of money in a sustained fashion just to have a system that is safe from government takeover? Libertarian ideology only gets you so far. Will libertarians put their money where their mouth is?

As for the bloated global financial industry, there are two points. First, it does more than just a simple ledger (think the overhead of dealing with fraud in a way that people are willing to accept). Second, it's plausible that Bitcoin will help de-bloat the financial industry, at least the payment services part, and that would certainly be welcome. That doesn't mean that Bitcoin will survive in the long run, though.

There's no proof that you need a distributed system to have a reliable public ledger.

There is at least some chance that a big awful corporation is more trustworthy than a plurality of miners.

> There is at least some chance that a big awful corporation is more trustworthy than a plurality of miners.

Definitely. But it's about central points of failure, not trustworthiness. The trustworthiness of a company is irrelevant if the government decides to confiscate all its assets.

For people doing transactions, I'm pretty sure trustworthiness is what it is about. Very few people in the US or EU have concerns about the government seizing assets held on their behalf (you can reply that they should have such concerns, but as a practical matter they do not).

Peercoin (eventually) uses proof of stake.

Bitcoin developer gmaxwell disagrees: https://qht.co/item?id=6798997

> In PoW when you attempt to mine you must expend energy and so you should only mine on a consensus which is likely to be the surviving one if you want your work to not be wasted. In PoS the same is not true, and an optimally rational PoS miner will attempt to concurrently mine all forks which he does not hate.

> Originally the signed blocks in PPC were supposed to be a bootstrap mechanism until most of the mining was PoS based, but then some clever miner started mining many possible histories and finding ones where he magically got lucky and his coins were the selected stake for all the blocks.

Yes, you have got it in one.