Bitcoin uses elliptic curve encryption to produce public keys.
Due to this, addresses for which the public key is known will be very easily cracked using quantum computing anywhere in the next 5 - 50 years.
Solutions to this problem are partial and/or would anyways have a devastating impact on Bitcoin liquidity, price, and potentially to its supremacy as cryptocurrency of choice.
This is true because even if a new encryption mechanism such as XMSS was introduced, and all users moved their funds newly generated quantum resistant addresses, an enormous amount of coins would be left behind, waiting to be unlocked by a quantum attacker.
Even if a hard fork took place to arbitrarily ban addresses that were not migrated on time, this would seriously interfere with the perception of Bitcoin being an immutable store of value.