Thats the wonderful thing about an analytical approach to things, wanting to find truth in something and questioning everything. Thats how I became an athiest to begin with ^^
Your right, it could just have well been a random guy who did a Joseph smith too, we could even put bets on what it was most likely, a man who wanted to become divine in the eyes of others, someone who wanted to make a cult so invented the character, maybe even a system of government who wanted to create there own laws, so put together there own myth to overthrow pre-existing ones like greek or roman.