Just know that Satoshi is very much around, and still involved in Bitcoin projects either by himself or in proxy. No one creates something like Bitcoin and backoff completely.
Unless that person is dead or in jail, and both possibilities are quite logical in everyday life. In fact, it doesn't matter at all who Satoshi really is, because everyone who wants to find out who he is, doesn't understand how important it is to this remain an unsolved mystery - unless someone thinks it would be better if Satoshi is still active and makes all the major decisions.
In the end, one of the most likely reasons why he left was that his closest associates started visiting secret agencies, and some others started complaining that he made all the decisions himself - which in the end was not good for his health or decentralization. The only logical decision was to disappear, which he announced when he left the matter in the hands of some other people.
With Satoshi's blessing, and with great reluctance, I'm going to start doing more active project management for bitcoin.