Scarcity can make a resource with value more valuable, but scarcity itself does not make something valuable by itself. It first has to have other characteristics that makes it valuable to users. Scarcity is like a value multiplier. If you have something with zero value, scarcity will not increase its value.

Bitcoin is valuable because it is money and being money that is scarce just multiplies its value. NFTs that are not valuable will not magically gain value due to its scarcity.

Let us assume there is a factory that can either build a sedan for transporting people, or trucks, for transporting goods. In order to make the vehicle, the factory workers as a scarce resource will be utilized and many scarce materials such as steel, plastics and petroleum products are also consumed.

In this factory each worker gets to decide if they are building a sedan or a truck. The end product will neither be a sedan or truck, since each worker can choose to use either sedan or truck body parts. It will be a one-of-a-kind vehicle, thus scarce, made with very scarce and valuable resources. But since it is not fit for either transporting people or goods it will have no value to either groups. The fact that it scarce will have no effect on its value.

This factory that randomly slaps body parts together and produces neither a sedan or a car is an example of NFT creation. Each NFT is unique and due to randomness some are more scarce. But scarcity can only make something of value more valuable. In the absence of any other characteristic it will still be of no value.

Now imagine a second factory where the founder decided that he wants to take on the evil truck cartel and that they will only produce trucks. People love the trucks and the trucks have become valuable. The fact that these trucks are scarce just makes them more valuable.

This factory is an example of Bitcoin. The fact that it is money is what makes it valuable and that only 21 million Bitcoin will ever be produced just multiplies its value due to this scarcity.