Bitcoin's scarcity isn't just a digital artifact; it's a marvel of social consensus engineering.
Even scarcer technologies may emerge in the future, but their value will be challenging to replicate.
You can use customize filters available on Coinmarketcap.com or Coingecko.com as well as other cryptocurrency market websites with similar filters and find many projects that have smaller total supplies than Bitcoin has.
I emphasize that altcoin projects have smaller total supplies than Bitcoin total supply and literally they are more scarce than Bitcoin in supplies. However, it does not result in any higher demand on such altcoins because they are very useless projects. Useless means no value, no value in turn means no demand, and price consequently must be low.