if he/she moves the original coins and proves that he/she is indeed Satoshi via technical competence and social consensus , then between the immense wealth and social status as the creator of Bitcoin their influence on the crypto world will be massive.
You can never decentralize power and wealth because they obey Power's law and also it happens organically and unspectacularly, it's simply a bunch of people agreeing that somebody is cool or what they are saying makes sense.
It snowballs from there and a couple of exponentials later that person is sitting on billions of dollars and a 70M people platform
Satoshi Nakamoto, net worth 30 billion and veto power over the entire cryptospace (if he's alive)
Vitalik Buterin , net worth 10 billion and veto power over the whole Ethereum ecosystem.
"Meet the new boss...the same as the old boss"