Do contracts expire when you're unsackable?

If I choose the become unsackable option in the in game editor, what happens when my contract expires? If you do badly, they obviously cant sack you, but can your contract expire? Or will they always offer you a new deal? Worst comes the worst you can always add years to it in the editor, but it's less fun that way.

Surely making yourself unsackable takes all the fun out of the game...

This.

Not if you are managing your favourite team and the whole point of the save is to manage them. But otherwise it definitely does.