Satoshi said the coins he had mined is like a donation to everyone. I can only think he completely forget all those coins and didn't even copy paste the privatekeys of it. Think of it like the supply has been reduced and this is why its impossible for somebody to prove he is the real satoshi. But then its easy to claim. If you have something to promote to the public, you can always organize a conference and have someone to claim he is satoshi to get more audience.
Hope it's true, haven't red this yet, will check this information, as many people are afraid that Satoshi might just making the priect up before he will finally sell it, and if ever it will be his donation, hope he can give it to different charity institution around the world as this will make them benefit more and he can be able to help those poor children that needs help.