When Bitcoin is lost, the associated cryptocurrency is gone forever. This is because there is no central bank or other authority that can issue new Bitcoin. The only way to get Bitcoin is through mining or by purchasing it on an exchange. When Bitcoin is lost, it means that the owner can no longer access their cryptocurrency.
NOTE: WARNING: Loss of Bitcoin is permanent and irreversible. Once a Bitcoin transaction is confirmed on the blockchain, it cannot be reversed. Therefore, it is important to take all necessary steps to protect your Bitcoin from loss due to theft, scams, or accidental deletion or loss of private keys. It is also advisable to store any large amount of Bitcoin in offline wallets or in a securely encrypted device.
This can happen if the owner loses their private key, or if the software wallet in which they store their Bitcoin is corrupted. If the owner of Bitcoin does not have a backup of their private key, then they will not be able to recover their lost cryptocurrency.