According to
Investopedia less than three million Bitcoin have yet to be introduced into circulation. We know that 18.5 bitcoins are mined till now. If I start mining bitcoin today, can I mine the last bitcoin? and what will happen when the last bitcoin mined? What miners will do after mining all coins?
This is a question I think impossible to answer! We will see at that moment, but maybe we'll be too old for this, when the last bitcoin waits to be mined by someone!
And in a couple of years, I strongly believe that we gonna get rid of paper money, bitcoind and other cryptos are used day by day, this type of question, what if....will be history.
I guess......