Given the current situation of the cryptocurrency market, the fact that the total supply of Bitcoin is only about 21 million, is easily forgotten. The recently mined 17 millionth bitcoin has served as a reminder of one of the core concepts behind the currency and the reason behind its high cost, it is in quite a limited supply.
Groups of people running computer nodes, which consist of computers, keep Bitcoin up and running. These computers store all relevant Bitcoin data, updating them as needed whenever a new transaction is added. Verifying these transactions come with a reward of about 12.5 Bitcoins. This means that, on an average, about 1800 Bitcoins are created daily. In previous years, miners were rewarded with more Bitcoins, however, a concept known as halving has reduced the initial 50 BTC reward down to the current 12.5 BTC. This is to account for the future rise in prices of BTC, thereby allowing a fairer market.
It has been estimated that, in about 120 years, the last Bitcoin will be mined. However, apart from the price, the power of Bitcoin in the market and demand for it will not dwindle even when there is no supply of it.