99.21875% will be mined in 20 years time. If electricity isn't very cheap by then and/or if bitcoin isn't worth hundreds of thousands of dollars, it's hard to imagine anybody wanting to mine then. How will transactions then be verified?
it is hard to predict future like this but i am pretty sure that there still will be people that will want to mine bitcoins not matter what, or their price will be large
True,
As time going difficulty level of mining blocks for bitcoins is increasing. And as per halving already price of bitcoin mining block reward is set to 12.5 BTC.
But as predefined price of bitcoin will rise more than whatever is current, so mining of bitcoin can be affordable for huge rig owner. Small units will not possible to get good ROI with mining.
And on more important things as maximum blocks will be solved transaction fee for bitcoin will be higher. So that will also advantage to miner for getting reward for verification.