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.
We all want what's best for Bitcoin, but nothing can make drastic changes to reduce transaction speeds or lower transaction fees.
Let me introduce you to this thing called the Lightning Network:
https://lightning.network/