For now, I have a very bullish sentiment on bitcoin as Satoshi said, in his own words, that the 21 million cap was an "educated guess". He wanted one unit to eventually roughly represent the value of one unit of fiat currency that people are familiar with, and struggled with where to place the decimal place given the wide range of adoption possibilities. There are only 21 million bitcoins that can be mined in total. Once bitcoin miners have unlocked all the bitcoins, the planet's supply will essentially be tapped out. As of February 24, 2021, 18.638 million bitcoins have been mined, which leaves 2.362 million yet to be introduced into circulation.