I also think that the government knows who Satoshi is and I am also one among the people who believe in a conspiracy theory that Satoshi is already dead killed by higher authority to stop or hinder the propagation of Bitcoin. They maybe somehow successful in hindering but these authority failed miserably in stopping the propagation of Bitcoin.
Why would the government kill someone that does not have any effect on btc? They would have known that Btc is decentralized and does not rely on Satoshi. Bitcoin was already being developed by other developers by the time Satoshi disappeared and if this conspiracy theory was true those developers and the current developers would be under threat.