Wow,this is a surprise to me...
I have always thought that satoshi may have deleted some of his wallet, because he may think that having so many bitcoins may be dangerous for the own bitcoin
If he wants to benefit Bitcoin, wouldn't he be giving away all those Bitcoins? IMO, it would be pretty dumb to intentionally delete a wallet. If you want to decrease the Bitcoin in circulation, just keep the private key and not spend your Bitcoins.