I spoke with Ninji just a couple days ago. I do *not* have any reason to believe they are dead, only that they simply have chosen to move on from this site.
Philosophically, sure, maybe that means they are 'dead as far as this site is concerned', and you won't be able to talk to them here any more.
But people move on from the fandom, they find other things they want to do with their lives, and sometimes that's a good thing.