If the alternative is Silva, I think I would give serious consideration to keeping BFS. Better the devil you know to some extent.
Would it be entertaining football? No, likely not; would it be effective? Yes; would I rather a season of attritional football that almost certainly guaranteed a top 8/10 finish (given how poor the general standard is outside of the top 5) vs. a year similar to Martinez's final one (which is what I fear Silva offers)? Yes, I think I would.
People are emotional about BFS, with some justification. There are things not to like about him and his football style with this squad to date. But, what can't be argued, is that regardless of the situation he finds himself in he typically finds a way to adapt which typically realises effective results.