Quote from: zvs on May 19, 2020, 06:03:12 AM

Difficulty will decrease if people quit mining. This will then make it more profitable for those that are still mining, or start back up. At least until the next difficulty change ...
-snip-

Logically its "stay profitable" not "more profitable". So when there are more people who quit mining, the difficulty will still be reduced.

Quote from: pooya87 on May 19, 2020, 10:13:23 AM

well based on what i have seen so far mining and how profitability and hashrate change over time is way more complicated than that. we can't really say this reason and that reason caused a rise or fall. there are many reasons involved.
of course price is the easiest to see and measure. but other reasons include the advancement of the mining equipment. for example during the 50BTC reward time people were mostly mining with their CPUs and with the mining algorithms (SHA256) that might have not been that optimized. then it was GPUs then ... and finally we are at ASICs which improve every now and then. and "improvement" means miner spends less while producing more computing power and earns more money.
another influencing factor could be fees. although most of the times it is a small factor. for instance during 2017 miners were earning up to 5BTC on top of 12.5 block reward in fees per block. that was around $30k to $40k additional income.

In my opinion, the price increase is better than other reasons that you mentioned since that other reasons also make the risk for the potential attacker becomes lower.
The chart of bitcoin network difficulty shows overall improvement and I'm sure its caused by what you said about the improvement of miners equipment that also becomes cheaper. This means the potential attacker can also have a higher hash rate easier than before.

So I can say that when this thing depends on the bitcoin price so it also depends on the potential buyers who want to buy bitcoin at the higher price indirectly. What if they don't want to buy it at a higher price?

And a high transaction fee is not good for the long term because people will hate to do a frequent transaction or at least make them think twice before making a transaction. So there will be fewer transactions.

But on the other side, this makes us realize the price of bitcoin will have a high chance to increase because it has to increase.

Quote from: Kemarit on May 19, 2020, 11:56:45 PM

My point is that this has been discussed many times already. I have said my piece, it's not worth a try.

Ohhh?? I don't know the relation between your answer and the thread that you mentioned because you didn't explain it.

Quote from: Kemarit on May 19, 2020, 11:56:45 PM

You talking about 2140? Again, why not look at the current circulating supply? We are closer to that 'almost all bitcoin have been mined", specially in the next 3 halvings: 2024 , 2028 , 2032. 1.5625 Bitcoin for Block ->225 Bitcoin every day. So it will be really costly to try and pull this 51% attack.

So whats your calculation about the 51% attack cost in the future?

Anyway, do you really think the purpose of this attack is only to get "more" bitcoin? And the equipment won't be able to be sold again?
If the case is as mentioned by figmentofmyass, the goal is not to profit from getting more bitcoin.