Satoshi knew that one day quantum computers will exist and will be able to move the early mined coins (P2PK) and created an unofficial prize competition to accelerate the development.
Maybe Satoshi created the greatest prize competition and the privatekeys are somehow within the blockchain.
Our guess is that he knew that the early mined coins will be moved one day. So he created a 'prize competition'. Otherwise he could move the coins to quantum resistant P2PKH addresses, but he did not and is not doing.The only question is:
Who will win the race and get the early coins?
Quantum computing or solving the "Satoshi Prize Competition".
Nobody can stop that race.