The Importance of Quantity in Economics

There's a hard cap of 21 million. Different research is saying that 4 million of Bitcoin is already lost. So my question is how do you think about this and will the whole world economy fit in the rest of the 16 million of Bitcoin? Yeah, I mean this is a fundamental disagreement in economics about whether you think the quantity of money matters or not. But there is a adult way of looking at it which says no, it doesn't matter. The quantity of money itself is irrelevant in itself if the value of economic activity taking place increases, the value of the money rises with respect to that.