Maybe it's a newbie question, but I suddenly thought about it.
In a few years (in terms of history), about 100 years, all the 21 million bitcoins will be on the market.
then, miner will get only transaction fees for processing the blockchain and no reward.
I believe that many of the miners will find it not profitable, and will quit out.
What do you think will happen then?
Theoretically, an equilibrium will form.
When the amount of
BTC goes down due to the lowering block rewards, miners that can no longer make a profit with the fees alone will shut off their ASICS, this lowers the diff, the lower diff will make it easyer for the leftover miners to solve a block... So the leftover miners will solve more blocks with the same hashrate and rake in more fees (so have a bigger income while their expenses stay the same)... In the end, the network's hashrate might lower a bit, but theoretically, that shouldn't be a problem.
Offcourse, how much miners will decide to turn off their equipment in the end will depend on how much fee/byte will be added on average, how big the blocks will be, and it will also depend on the bitcoin price...
This equilibrium is really complicate.
from one hand, when it'll happen the bitcoin price will start to rise since there will be no flow of new coins.
but since there will be less miners, the fees might be higher, and really expensive to spend bitcoins.
but then again, if it will make people use it less, the price will go down, and even less miners will stay on the stage.
I know it will happen in more than 100 years, but I'm afraid it might be the end of this wonderful coin.