It's a game of chicken from now until the end of the season. If he stays and starts next season looking like he's not learned any lessons from this season then at least there is plenty if time to get someone new in. Best case scenario (other than Bob getting it right next season) is to win the EL so that we can attract a manager who wants to play in the CL next season.
I understand the sentiment here but a lot of people have said this but it is easy to forecast the judgement of circumstances when not in that moment.
If we stay up and he starts next season, what would be the trigger for his position to be untenable thereafter? Failure to meet a set points total having played 10 games/15 games/20 games? Playing style remaining the same?