I don't see how it could be profitable. If it can't be profitable, then the risk of someone doing it is pretty low. If they already have the necessary hardware, they'd be much better off mining.
If you're not trying to profit from the double spend itself but rather from a collapse following a proven double-spend, you can double-spend the bitcoins to yourself.
That's incorrect. Security scales with USD-denominated rewards, not BTC-denominated. And there are 16 years of real-world data showing they have been generally increasing, so a healthy sign that the Bitcoin experiment is working:
https://newhedge.io/bitcoin/block-reward-per-block
And not only that, but rewards are still expected to stabilize even when measured in BTC (thereby not relying on an increase of BTC's price) as they are progressively composed more and more of tx fees instead of newly mined BTC.
It's puzzling to me why some still don't understand the systemic incentives that make all this work as it has for 16 years and counting...
Then I guess you're the type who will be really surprised to learn that with diminishing rewards comes increasing consolidation.
> ... that make all this work as it has for 16 years and counting...
That's convenient way to memory hole the market flash crashes, network forks, the blocks mined without consensus, and everything bad that happened over that timeframe.
For L1 fees to actually increase over time, we need increased L1 throughput. Without that, increased demand for transactions causes more batching of transactions (mostly between exchanges).
Given the failure of BCH for pseudo-religious reasons I don't have much hope.
Says you, without a hint of a rationale backing your argument.
It seems to me that the historical hashing rate curve tells a different story.
And block rewards have been diminishing regularly (and very predictably) pretty much since day one.
> block rewards have been diminishing regularly
That's exactly what the poster you're replying to argued; the BTC denominated block subsidy halves every 4 years, and so without a corresponding doubling in price, the bitcoin security budget keeps diminishing, at least until tx fees start to dominate the subsidy.
I would have expected such security rules are part of the miner code, no? Don't they need to consider rules related to the comparative security level of a chain when decided which chain to follow when multiple exist?
However, as Bitcoin's security inevitably weakens over the coming years due to diminishing miner rewards (denominated in BTC), I believe this "6-confimation" acceptance policy will change to include not only the number of confirmations, but the timing of those confirmations as well. Consider a scenario where an exchange deciding whether a tx with 6-confirmations that took 4 hours to arrive (this happens occasionally) is safe to consider finalized/settled. Even though 6-confimations may be considered safe by today's acceptance policies, this tx would still have a high probability of double spend due to the assumed 4-hour long wait for the 6 confirmations (as the attacker would have 4 hours to produce 7 blocks instead of the normal/expected 1 hour). Instead of ignoring block interarrival timing, it may make sense to include block timing as part of an acceptance policy.
So, going forward Bitcoin acceptance policies may change from today's 6-confirmation standard to something more complicated that involves the amount of time those blocks took to arrive. This would significantly enhance Bitcoin's double spending resistance without adding/altering any code and may give the network a much needed security boost in the coming years to prevent the attack discussed in the post.