Guardiola hasn't been sacked, but it is not only because he knows his worth, it is also because he is the best coach in the world in terms of influencing players and making them better. I doubt that Klopp would ever be sacked as he is very similar and both have their successes. They would rather leave a club in agreement with the clubs' bosses, but not get just fired I suppose. They are also different from Mourinho who likes to provoke everyone, including officials from his own clubs. He is more likely to get fired at the end of his engagements than to go just because he doesn't want to stay anymore.