This is true, you need demand too. But NFTs make scarcity possible in a domain in which it was not possible before (digital art, for example). You have demand f

This is true, you need demand too. But NFTs make scarcity possible in a domain in which it was not possible before (digital art, for example). You have demand from collectors and speculators who want to create a market for "scarce" digital art. You have supply from creators who are quite happy to meet that demand. And you have NFTs, a way to make digital art scarce (for some definition of scarce.)