Satoshi is no god or some higher tier. He is also a human and maybe when he gets older he wants to buy a nice isle with a house.
So, why should he or any other early adopters would not "dump" his coins?
All his work would be useless if he didnt dump his coins, because then he wont have anything to live...and he wont be rich.
Meanwhile i think this perma dumping is done by someone like satoshi who was an early adopter and has "unlimited" amount of coins...
In the end, bitcoin gets stronger out of it because the coins are shared between more users, but the value will go down.
