Bitcoin has a limit: only 21 million BTC will exist. Due to a process called halving, the amount of new Bitcoins generated decreases every four years, and the last BTC will be mined around the year 2140.
When that happens, miners will no longer receive Bitcoin as a reward, but will depend on transaction fees to keep the network active. This will make Bitcoin even scarcer and possibly more valuable, as its supply will never increase.
Basically, Bitcoin is like a limited resource, similar to gold, but digital. Its scarcity is what makes it unique in the financial world.
