It's already been plausibly suggested that he was on an automatic bill-paying plan. That's one of the things that got me about this story. So much of our lives can be put on automatic pilot these days that a person could die or disappear, and still appear to be officially present and accounted for. Sounds like a potential plot for a novel or a screenplay!
Hard to believe that someone could EVERYTHING on automatic and yet not receive something like the newspaper that would begin to pile up. What about the guy's mail? Someone might want to talk to the mailman unless there was a slot in the door that accommodated a LOT of mail.