[thesz]

Add 50 more - to reduce hash rate even more. Announce hard fork right after difficulty adjustment. And then, suddenly, these who have not forked will be stalled for several weeks. Instead of 10 minutes per block, the time will be 30 minutes and possibly more. And to adjust the difficulty those who have not forked would need... a hard fork?

Yes, these 100 miners are pools. But where pool participants will go then? Will pools who have not forked keep pool participation fees low?

Etc.

The game here is not quite simple. It is much more complex than appears at first sight.

[tinus_hn]

The difficulty adjusts automatically. Bitcoin wouldn’t have come this far if it were that fragile.

[jstanley]

It doesn't adjust immediately though. If a large majority of miner suddenly disappears then the block mining rate does indeed drop until the next difficulty adjustment.

[tinus_hn]

So if 50% of the mining power left the next block would take on average about 20 minutes. Where it routinely takes about that long, because that’s just the way statistics work. A non issue.

Here’s a graph of the time blocks took over the last three years:

https://bitinfocharts.com/comparison/bitcoin-confirmationtim...

Look at the peaks and try to remember the issues that resulted in.

[thesz]

First, 20 minutes in average for power-distributed time-to-block would result in much, much higher peaks. In your chart I see 25 minutes for a block, then it will be 50 minutes.

Second, instead of two weeks to hash rate adjustment, it will take four weeks.

And if these staying with this slow bitcoin would decide to leave to more profitable currencies (not necessarily Bitcoin, there are other SHA256-based PoW schemes), that will push hash rate adjustment even further into future.

[tinus_hn]

These 25 minute peaks were caused by a similar event, witness the also slow rates in the surrounding blocks. So that’s approximately how bad it would get in this ‘disastrous’ event.

https://www.cnbc.com/2021/07/03/bitcoin-mining-difficulty-dr...

We survived.