We may never know what could happen with those bitcoins satoshi owns, it is not something we can even predict. If satoshi is real and it is just one person, and if he is alive, he could simple come down here and sell all of his bitcoins and use that money to live rich forever, but honestly you see what is going on with XRP so I doubt it would be the case, if he did that there would be a ton of people and governments who will want to question him and probably even jail him.
But what could happen would be some hacker finally managing to get into satoshi's wallet, I know it is very very difficult but there must be some people who have been working on it for years now, and if you give it enough time and juice, we could potentially see something like this happen, it might take a long time but it could at least happen with enough time, so I guess we could see those bitcoins sold on market after a successful hacking.
We do not know for sure. But if I were him, I will not show myself to the public because that can make me in danger. After all, many third parties want to know more about me. I do not want to show myself here too, because I know that in this forum, some people still secretly watching the forum to find out about satoshi nakamoto.
I think Satoshi Nakamoto already prevents the hacker from hacking his wallet by using many things security layers that we might do not know. He is the creator of bitcoin, he knows the code, so I am sure he knows what he needs to do to secure his wallet. The bitcoin that will be sold at the market will come from the bitcoin that already gets hacked on the exchanges.