If you're part of a number of regimes deemed to have failed then you go. Simple as that. If that wasn't the case we'd have a string of first team coaches from the Martinez/Koeman/Allardyce years all with a legitimate case to stay on "because we dont know what good work they do if any".
The argument is spurious. He's been part of many coaching teams that all left the club when it was time for them to go. So why are we keeping hold of him so long? He was front and centre with Allardyce and giving him advice during matches FFS!
The feller is on the easiest gravy train there's ever been. There is NO justification for him to be retained in the dugout whatsoever. He is a curse.
BTW, for that ^^^ reason I think, for all the talk about Silva keeping him, he'll be nowhere near our front bench. Silva values his confidants and like-minded tacticians. No room for a galoot in that company.