It's not a theory it's a fact there has been real no damage done, its not man united or Liverpool where the squad needs big overhaul.
We aren't in loads of debts if he doesn't sign a contract whether he leaves this season or next there will most likely be champions league football.
A new manager will have their own coaching set up and their own ideas of how to get the best out of current players and new players.
So what is this damage?.
Yes he has failed in match preparation, having a team that's mentally and physically strong and hasn't played well this season.....but we are in third not Chelsea's position, so this damage is ephemeral.