...and that proves the point. There is no such thing as a non-combat adventurer. Bookish expert of rare knowledge is Indiana Jones they dont stay just bookish experts of rare knowledge if they do any kind of adventuring. Once you get character growth, you get combat competence.
C3-P0 is comic relief. R2-D2 is a henchman in the Star Wars movies and IS a combat character when he gets the spotlight in supplementary fiction.
3rd edition Wizard can be a non-combat character. If you don't believe me then I can build you one.