Well, for one reason, if Satoshi is alive; he can easily crash the entire bitcoin market if his wallets start selling currency. If he's dead, (which is the cas

Well, for one reason, if Satoshi is alive; he can easily crash the entire bitcoin market if his wallets start selling currency. If he's dead, (which is the case if he's Finney), then that is a not a risk. If he is alive, then the likelyhood of him cashing out at some point is pretty high. He may be only be waiting for the moment when there is enough liquidity in the market for him to dump it all at once - and we're probably not quite there yet, he's said to have just under 1M BTC.