Besic, Gibson, McCarthy or Barry would never be a CAM.
They all play well because of how they play deeply. Don't misconstrue being a good technical player as a cm, to be an opening to play further forward.
It doesn't work like that, and it 99.9% won't work. And i can bet my house on it not working with any of our cm's.
It's about a lot more than the technical aspect, it's about positional sense, about knowing that area of the pitch etc, and most players just don't adapt to that.
Baines couldn't play LM for that exact reason. Oviedo struggled at LM/RM for that reason too. Coleman went badly stale at RM because of it also.