Effects of Supply on Bitcoin's Price
The supply of an asset plays a vital role in determining its price. A scarce asset is likelier to have high prices, whereas one available in plenty will have low prices. Bitcoin's supply is generally well-publicized, as there will only ever be 21 million produced and only a specific amount created per year. Its protocol only allows new bitcoins to be rewarded at a fixed rate, and that rate is designed to slow down over time.

Therefore, Bitcoin's future supply is dwindling, which adds to demand. This is similar to a reduction in corn supply if harvests were to be reduced every four years until no more was harvested, and it was publicly advertised that it would happen—corn prices would skyrocket.