While one OP created a thread about how Bitcoin will take over the global payment word in the future, and I tried to understand that Bitcoin itself is limited to 21 million only and its increase is not even certain, which eventually might end up with a yes/no answer. And it's going to take more than some decades to change from that.

So curiosity made me ask why it is limited and why more can't be made before those decades. I'm just a beginner with little to no knowledge about bitcoin technically.