Form especially in tennis can be extremely transitory, but when you consider Djokovic and Andy there are striking similarities between the two’s progression ( abet with Andy twelve months behind).
So if Djokovic can lose his form so dramatically after a his first slam win what makes Andy so different?
Or is it once he wins a hard court slam all we have to do is sit back and enjoy twenty back to back hard court slams for the next ten years (excluding injury).
It's a fair point and I guess we can't know until Andy has won his first slam and progressed/declined from there on. I just have a belief (possibly the product of bias!) that Andy wouldn't allow himself to slip. After Oz last year, Djoko kept up his form by winning Indian Wells and Rome (the latter admittedly was a tournament in which Nadal was injured) - I'm not sure what made him lose his form. He made the semis of the French, the final of Queen's, the final of Cincy and the semis of the US. Of course there was the Wimbledon 2nd round loss in between, but that's not a bad record by anyone's standards. The clay season belongs to Nadal at the moment so perhaps as Djoko could not keep his early season momentum going and translate it into solid titles (despite still making semis and finals), it sapped some of his inner belief, causing the relatively poor end to the year (the Masters Cup being a real season-saver by that point).
As Mark says, Djoko is far more of a joker, while Andy seems to have been so driven for so long that now that he is nearing his best, I don't believe he would allow it to slip.