Guys, a question arose in my mind so I am here with it.
Just think, when 21 MN bitcoins get mined completely and miners won't get any more rewards except fee, will they still do the mining?
Somewhere around the year 2140, long after we are all dead and gone? Not sure why you care, but if bitcoin still exists at that time, then the fee will generate enough revenue for miners to continue. If the fees aren't going to be enough, then the miners will have stopped and Bitcoin will have falied LONG before the last piece of the last bitcoin is mined. For 4 years before that, the block subsidy will only be 0.00000001 BTC per block. For 4 years before that, the block subsidy will only be 0.00000002 BTC per block. For 4 years before that, the block subsidy will only be 0.00000004 BTC per block.
That's 12 years before the end of the block subsidy during which the block reward is less than 0.00000005 BTC per block.
If they won't, mining will stop. How will blockchain move the transactions ahead? How will the network run?
Either they will (in which case everything will be fine), or they won't (in which case the transactions won't ever get confirmed. Of course, it only takes 1 miner with 1 CPU to confirm transactions, so you could always just run your own mining to confirm your own transaction, but the lack of security in a blockchain with so little hash power behind it would mean that it wouldn't really be worth anything at all, and nobody would want to use it. Lets hope that the transaction fees are enough so that doesn't happen.
Will we see a dump when it ends or a new rise in the value?
Probably neither. If bitcoin is still in use more than 120 years from now, then I suspect the exchange rate will have stabilized. When the block subsidy drops from 0.00000001 BTC per block to 0 BTC per block, there will probably be no direct effect on the exchange rate at all.
My purpose to ask this is to know the possibilities bitcoin will face in the future after this happens, and I think this will not take much longer, not more than 1 and half year.
You are incorrect. It will take more than 120 years until the block subsidy drops to 0 BTC. It will be 12.5 BTC for the next 4 years. Then it will be 6.25 BTC for 4 more years, then it will be 3.125 BTC for the 4 years after that, then it will be 1.5625 BTC for the 4 years after that.
That's at least 16 years with the block subsidy higher than 1 BTC.
But why would someone mine knowing the fact that they will just get few pennies for their work?
Even with cheapest electricity possible, you won't break even your costs with that small transaction fee when mining will end up after all coins mined.
If every transaction pays a fee of at least 100 satoshi per byte, a 1 megabyte block can generate a total of almost 1 BTC in fees. At today's exchange rate, that's much more than "pennies". That's more than $700. As long as the mining difficulty drops low enough, that would cover the cost of the electricity and leave plenty of profit. If the difficulty doesn't drop, then that will mean one (or more) of:
- Miners have discovered much more efficient ways to mine
- The protocol has been enhanced to allow more transactions per block
- The buying power of 1 BTC is much higher than it is today
One more question:
Will developers decide to increase the number of bitcoins if this happens?
Very very unlikely.
Is it in their hands?
No. It is in the hands of the people running full nodes.
If this takes place, will the price remain the same?
Impossible to predict, but my opinion is that an increase in the maximum amount of bitcoins would result in a complete collapse of bitcoin exchange rate as everyone loses faith in the incentives built into the system.