There is no proof that the wallet had up to 1 million coin at any time and the wallet is as old as bitcoin itself with the last sent coin in 2009. So where does the rumour of the 1 million bitcoin possesion comes from?
So far the numbers are just speculation as we never really know how many bitcoin he has. Satoshi clearly has a way of keeping his privacy so that people don't easily find out how many bitcoin he has. I'm sure he has multiple wallet, so even if someone finds out about one, they probably won't find the other.
I still believe that satoshi is not an individual, its a group of people. If he has the forum then there are chances the forum members related with him at a point and know his whereabouts?
I think otherwise, a single person satoshi is not a group of people and even if we convince one of them to be right, then I don't think we have any evidence to vouch for its veracity. My logic about satoshi is, he is one person considering it is very impossible for a group of people to share the same idea through one account called
satoshi.
This is most probably not the Satoshi wallet, instead, one of the many addresses from his wallet(s).
But as said, which are his wallets (or addresses) and how many bitcoin he actually own are all speculation and educated guesses, nothing is known for sure.
I also don't think it's his only wallet, so it must be one of the many purses that satoshi has.