Very weird tack to take, telling people the jury won’t respect them if they bring a goat to the end. Like, thinking the jury will admire you for bringing a threat to the end is one of the most disproved ideas there is in Survivor.
What Bill should really be doing is selling why Bobfather needs him to make the end. Ie if I’m in f3 they’ll need to vote me out. Maybe even throw in a F2 promise.
Yeah, there are ways to argue that someone who seems like a goat is actually more threatening than it seems, but this isn't it. And you're right that making an argument that they need each other to actually make it to the end is a more convincing argument, at least to me. It's an easier sell because it doesn't rely on altering the other person's perceptions. And Bobfather is the kind of person who imo is extremely committed to their perceptions of the game and unlikely to be willing to change them.
The main problem for them working together, apart from their apparent dislike of one another, is that Bobfather and Bill also see each other as one another's biggest challenge threats, so if either of them thinks that their odds of being beaten by the other in the F3 challenge are greater than their odds of losing the challenge to the other two at 3, then it does make sense to vote the other one out. So it arguably could make sense to gamble on winning the final challenge, especially since Crystal and Carmine have been fairly mediocre at challenges thus far. Bobfather especially I think is extremely confident in her challenge ability.
I don't like it because I don't like leaving things up to chance, but I think there are rational arguments for why it might make sense.
And of course, the other problem is that while Bobfather and Bill seem incapable of getting on the same page, they also don't seem to realize that Carmine and Crystal very much are. I don't think a 2-1-1 is likely next round because both Carmine and Crystal seem to recognize that they are each other's best bets, and as long as that's the case, they are unlikely to vote separately. But even so, in a 2-2 I'd definitely give the advantage to Bobfather and Bill just based on their challenge records thus far.