Satoshi has a
balance of nearly 1 million BTC, let's guess what will happen if the wallet can be accessed by someone, whether it's the owner or maybe a hacker. Will the price of Bitcoin start to crumble and start not selling?
If it's the case that a "hacker" manages to gain access and if the hacker does dump it, sure. But that's a huge "if". We're talking about a person or group that has managed to stay anonymous for a decade here. You'd assume that he/she/they know how to secure the coins.
There are a lot of possibilities, satoshi could've forgotten about that 1 million bitcoin and never bothered to find it, that seems ridiculous but that can still happen. We will never know because we do not know who is behind the curtains of the account satoshi. Best thing we could do is honor satoshi's wish to be anonymous and cherish the brainchild that is bitcoin.