Think this is a really interesting point. You could argue it probably makes sense for managers in other walks of life too. If the answer to all your problems is spend more money, maybe you lose sight that hunger is more important than talent a lot of the time. You look at the money Pep's spent on fullbacks, and not one of them can hold a candle to either of ours, both of whom strike me as the absolute hungriest footballers you could ever wish to meet.
It makes sense in any aspect of life. Early consistent success can actually stunt growth and development. Failure is actually the best opportunity to work on aspects of a business/club/player/organisation/initiative/political structure/ personality etc. Being forced to face failure and having to either create new paths or strengthen and streamline current paths and habits, is how we grow. Facing success consistently makes it harder for us to adapt to failure, and one if the additional risks with consistent early success, is success becomes intertwined with the perception of self. So a successful person that rarely tastes failure, thinks the success is the main part of who they are, rather than an outcome of a successful strategy or habit. Once they taste defeat, the insecurity from losing their sense of successful identity can lead them to depresssion.
In a sense, having faced failure and regrouped to try again, is so important to have on a CV. I absolutely believe that Klopp's near misses with promotion at Mainz, Cup Final losses with Dortmund, and near misses with us in the league and Europe, is why the atmosphere at the club is both calm, yet incredibly focused and hungry and ruthless. We've tasted defeat as a club, and never want to taste it again, but having faced it before, we don't fear it. We've failed before, and realised the next day the sun rises same as before and shit goes on as it once did. Life is bigger than a loss, and Klopp constantly makes statements about the value of a loss. I remember early on in his reign when we were initially unbeaten for the first 5 games or so, he mentioned that he's happy we were unbeaten but that we woukd learn more from our losses.
Pep and Mourinho are on the other side of the spectrum. Losses and defeats, especislly high profile ones, I think play a very large emotional toll on them. If City fail to win Europe or the FA cup, or if we also end up winning in europe or the FA Cup, I think he'll walk away. Take a year break and end up at PSG or Juventus.
