It was capped at 21 million by Satoshi Nakamoto to create scarcity. This is one of the features of Bitcoin and that way, there wouldn't be issues of inflation.

Bitcoin supply limit or hard cap is usually reached by a process called the halving which occurs ever four years and it has been revealed that the last Bitcoin would be mined in 2140. As to the question of if anything could lead to the change of the supply limit, the answer is nothing because this supply cap is controlled by its incentive and governance model which means that despite the desire by miners to change this design so that they can make more profit, Bitcoin doesn't have the incentive to change cause that would affect its core investment theory which is scarcity and would also result in inflation like I stated earlier.