Keeping privacy on the internet is a mixed bag.  On one hand, it can be easy to blend in.  But someone that is determined can very likely ID a significant percentage of people.

I'm betting that some people know his or her true identity.  People that were around at the time.

I think I read that people have studied Satoshi's writings in comparison to known people that were in the Cypherpunk community and potentially could build a circumstantial case to identify the person.  Personally, I consider that an invasion of privacy.  If someone chooses to remain anonymous, I respect that choice.

I do sincerely hope that he or she has been able to enjoy some measure of success from Bitcoin.

And who knows, maybe one day he or she will reveal themselves to the world.  Legitimately (I believe there have been impostors).  That's entirely up to them.