Don't see why it has to be absolutely black or white? Billy not playing well, ergo: career over...
We've got a squad, why not use it? In the same way that Edna's not being great recently, give Danny Lafferty a run for a while, but no need at all to reach the conclusion that Edna needs a slap & to be shipped off back to Portsmouth.
Billy's had poor runs of form before, especially under the Goose Plucker, but we weren't in a position squad-wise to drop him back then. But things are different now.
In saying that though, CW's got to maintain harmony. He's not gonna want to alienate the single most important person in creating the squad cohesion & happiness that's been enjoyed in recent times. Not an easy situation.