Because there's a fixed amount of it, but not a fixed amount of people, and not a fixed amount of demand for economic activity/transactions, which makes it defl

Because there's a fixed amount of it, but not a fixed amount of people, and not a fixed amount of demand for economic activity/transactions, which makes it deflationary. It's not that it's explicitly shrinking itself. It's that it's shrinking relative to other factors because it has a fixed supply.