Listening to Webber, it sounds like he is better able to get the car setup since he has said a few times his feedback and changes are going into Vettel's car. Getting a driver with the ability to communicate well with the engineers is not always easy so it might be Vettel wouldn't be doing so well on his own. Certainly, replacing Webber with a 'junior' driver would lose them quite a bit of experience...
Anyway, I think Webber needs the extra incentive the drama is bringing to stoke the fire in his belly, maybe Horner sees this too and is purposely inciting a little controversy, after all it also helps getting Redbull in the news Maybe they all get bonuses for every article that has the Redbull name mentioned, they sure are getting a lot of mileage out of it all.