[once_inc]

Environment FUD refutation (just the one I personally link to most):

https://www.coindesk.com/business/2021/03/05/the-frustrating...

PoW security is a vector, and doesn't flip from secure to insecure at some specific point. A gradual reduction in mining hash rate doesn't render the chain noticeably less secure.

Feel free to fork Bitcoin and use it as an alternative. Please note that this has been done in the past, and will probably be done in the future. There is a reason why the economic majority remain with Bitcoin, even though PoW isn't energy neutral.

[giaour]

> PoW security is a vector, and doesn't flip from secure to insecure at some specific point.

The network does flip from secure to insecure whenever the cost of mounting a 51% attack dips below the amount an attacker could expect to gain. Markov and Schoar [0] made a convincing case last year that as minted rewards from mining drop, the active mining pool will naturally shrink and become more and more vulnerable. PoW does not prevent misbehavior; it establishes an incentive system to encourage participants to behave properly, and that incentive is subject to realignment by market forces.

[0]: https://www.nber.org/papers/w29396

[danuker]

It's not a network-wide flip. Certain victims suffer only, and they are very few - the ones not waiting for enough confirmations after receiving a large amount. For example, right now with a cost of mining of $1M/h, after receiving $2M, you should wait for 2 hours (12 confirmations), before accepting it as settled.