Yakubu probably got sick and tired of being asked to run the channels, Steve Kean actually said something in a post match interview about using Yakubu in the right way, and that he specifically told him to stay near the 18 yard box and concentrate on scoring goals.
It's no coincidence that the same has happened with other strikers, it's the
Moyes way. Saying that it's Yakubu's fault when he is being asked to do a job which stops him scoring goals is silly. The same happened with Saha to an extent, the amount of times he would be running down the wings leaving us with no actual goal threat was infuriating.
The whole 'Yakubu only plays well in his first season' malarkey is laughable and always has been, because Everton is the only club where he got noticeably worse, and it was after a terrible injury.
And don't think i'm excusing their laziness, because both Saha and Yakubu didn't help themselves, but they were also both used in completely the wrong way. Saha as a lone striker being hammered with long balls was a total joke. We desperately need some good offensive minded coaching staff.