If Satoshi is alive and still has his keys, he will probably start selling only when there is no bitcoin to mine anymore and it's value so high that 1 Satoshi would equal $1000.00. So I don't think it would sell just at the beginning like it is today !
If one satoshi would be 1000$ , a bitcoin would be worth 100 billions, and all the coins will be worth 210 000 trillions.
Unless we colonize Mars and Europa there is no way for this to happen.
Guys the problem is not that the price could go to zero if he decide to sell all the bitcoins. The problem is giving so much power to a single group o people.
What power ?
His only power is to blackmail (what?) by selling coins for fiat on the markets in order to drop the price.
Now, who will he blackmail with this? The governments? They don't care.
The exchanges? The bitcoin gambling sites? What could he demand from those ?
Even if he sells all his coins, if he still has them that is, he will only manage to crash the price briefly and after that all the fear from a dump will be gone forever.
Satoshi probably does have upwards of 1,000,000 Bitcoin actually. That amount is kind of an illusion though, because it would be almost impossible to sell that many in a short period of time. The value is mostly conceptual due to this. Sure, it is worth ~$5,000,000,000, but in reality he might be able to get a few hundred million of that out before the market tanked hard. So I think generally speaking is the case with most early adopters.
Right now just selling 2000 coins will get the price down by almost 700$, so with a sell of 10 000 coins on 3 exchange he will reach the point where he is getting hundreds for a coin or even one dollar per coin.
Dumping 1000000 coins would be overkill and it won't serve him at all.
Besides, the moment those coins start to move the market will react and not in a good way.