In a way, a charismatic player is probably "beating" the game in the same way the archetypical "DM's wife/girlfriend" supposably does...
Possibly in some cases, but the usual complaint with the wife/gf is that the DM won't kill her PC, gives her the best treasure, etc - without effort by the wife/gf. I think that's distinct from in-game effort by the charismatic player giving a good result for him/her.