I have to disagree, right off the bat it circles directly to this forum regarding Gavin heading to the CIA.... then it again alludes to why Satoshi never made "himself" public after inventing the technology.
I'll go with the most logical explanation: Satoshi has never been seen or heard from because he does not exist.
So one person with the smarts to make bitcoin could not 'disappear'? He has indeed done a great job of not making tracks in the first place. But I can not say it would be impossible to go online anonymously for the time he did. Even mybitcoin.com did it, and basically left no firm tracks and people have a financial reason to look for him.
Satoshi has not committed any crimes nor has he wronged anyone. This makes it a lot easier to 'disappear'.