We don't know whether quantum computers will exist or not, but assume they will be built and some QC owners will move the early mined coins. What will happen?

Case 1
They (QC owners) could move the early mined coins, which are mined to P2PK addresses and haven't been moved since then.
They could let these coins there for a certain time to give potential owners the possibility to prove (signed message) that they are the owners and transfer these coins to them.
If there is no owner, the QC owners are the new owners.

Case 2
Some BTC owners will not accept case 1. They will create a hard / soft fork and burn these early mined coins.

In both cases we have to implement QC resistant addresses immediately.


Case 3
They (QC owners) will move all possible coins (also from active addresses).
In this case the Bitcoin price would collapse and it would end the Bitcoin project.



Case 1 gives the QC owners the possibility to improve our Bitcoin network and make it quantum resistant and reward them with these early mined coins. If there are still owners of early mined and not moved coins, they have the chance to move the coins and will get them back even after being moved, if they prove it (signed message) within a certain time period. Case 1 would lead to a smooth transition to a quantum resistant Bitcoin network and would be the strongest fork.