I have wondered if he somehow slipped into the identity of someone who actually was a hermit named Ben, who may have died unbeknownst to the locals, and had very little contact with anyway, and had a cozy little hovel beyond the Dune Sea. 😃
If the real Ben was killed by Tusken Raiders, it would add a dimension to how they freak out when Kenobi appears waving his arms and making scary noises.