It's the question I dared not ask (though have alluded to). It doesn't surprise me there is speculation. And I'm afraid mine is going to a long response, because there's a few facets to consider, so hang in there....
I was a defender of the Sky stated tactics re Cavendish before the tour (still am) but even I was still a little surprised at how much effort was put behind the yellow jersey. Sky made sure of their goal. I did wonder how much of Cavendish's goal of Olympic gold actually suited Brailsford's Sky goal (but that's the sort of question you can never answer). It's possible that Cavendish thought/was told he could have more support in 2013. With the rise of Froome, how does that now play into Sky's thinking? And how will Cavendish respond to that?
Then I think of what Cavendish might want. I felt really excited that he might remodel himself into a classics rider (and he seemed to hint at that), and I thought Sky was the place for him to do that. He'd still be a green jersey contender but of a different sort, and one that could get by with less support (like Sagan). That'd suit Sky and Cavendish.
Above all else, let's not forget that Cavendish has had a good year by most standards. Ok, some might not feel that way because he wasn't all conquering at the TdF but he's notched up good wins none-the-less.
I've always thought this would be a transition year for him but I don't know. So much now depends on what he wants for next year and I really do think Sky have got a balancing act to perform. And let's not forget EBH - he's had to make sacrifices too this tour. It's probable he aspires to more than the 'super domestique' role.
Yep, it's going to be an interesting meeting at the end of the season for Sky as they set 2013 targets. They've had a great year, succeeded in their objective and come away with plaudits. At the price maybe of some of the team feeling a little neglected and unfulfilled personally. We'll see changes in the line-up, that's a given, but as to who they'll be depends so much on what those individuals want. And that we just can't know. It grieves me to say it but I think they'd let EBH go.