Taking the term literally, there are very few legitimate 'roleplaying' games - certainly fewer than exist within the RPG genre. How many times, for example, do you remember actually feeling at one with the character you controlled?
How many times did you share not just their experiences and actions, but their mind and body as well? Rather than give you ownership of a character's stats and inventory, how many games give you the sense that your character in part has possession over you?
Not many, though The Chronicles of Riddick is one.