My dear , don't be so conclusive in your assumptions, I believe there is a good reason why the wise man said ~ No body is above mistakes.
Even highly trained professional drivers still get involved in motor accidents on the high way.
Though I am not trying to say that I believe that satoshi has actually lost access to his bitcoins, but what I am saying is, if the real satoshi(after proving above all reasonable doubt that he is the real satoshi) comes out to say that he lost access to his bitcoins, then I don't think there is any need to doubt him, even the most careful people still sometimes, made mistakes that cost them their lives.