Even Theymos doesn't know the identity. He have helped through the forum. Even now he might be around the forum with some other name going through different discussion taking place about the future of bitcoin. Some might've participated on random discussions, but never thought of Satoshi being this genius. More users of his time weren't active on the forum.
Or even now he's laughing watching us talk about it every day on this forum. Maybe he could disguise himself as who he wanted to be without worrying about his identity being exposed. If I were him, perhaps revealing who he really was would be dangerous for the FBI to target. Lol