Knees get shot, sharpness fades, minutes have to be managed. For sports fans, the idea that athletes have a limited shelf life is not a difficult one to accept. It’s always hard to watch your favorite player lose a step, but it’s never totally unexpected. A playing career is divided into three acts: the early years, the peak, and the decline. The duration of each may vary, but the sequence does not. It’s the reason why fans revere that rare breed of players that can stave off decline and enjoy prolonged excellence. We recognize that Ryan Giggs, Paolo Maldini and Javier Zanetti are the exception, not the rule.

Why then, is this same logic so rarely applied to managers? Managers are almost exclusively judged against the peak of their success, with little or no context applied with regard to the passage of time and its inherent challenges. The list of managers who defy this notion,and manage to maintain a level of excellence over decades is very, very short. Sir Alex Ferguson is the premier example, and among “active” managers, perhaps only Carlo Ancelotti fits the bill. These exceptions aside, the overwhelming evidence points to this: Just because managers aren’t sprinting up and down the touchline every week, it doesn’t mean that they don’t eventually get washed up, too.

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For some of those managers whose powers have waned over the years, much of it is because the very same principles that they helped pioneer have become so ubiquitous that they no longer represent an advantage. When Arsène Wenger took over at Arsenal, he revolutionized English soccer. His knowledge of then lesser known markets for players made him a shrewd mover in the transfer window, just as his emphasis on proper diet and nutrition gave his teams an added edge. But in the decade since his last league title, the rest of the league has learned from him – lesser managers have caught up, and rivals have passed Wenger by.

Manchester United fans have found themselves wondering what happened to the manager they thought they had appointed to succeed David Moyes. Louis van Gaal built his reputation on teams that controlled possession and dominated games. But in the two decades since his greatest ever team — the all-conquering young Ajax side — the sport has caught up to him as well. The Premier League is one where even title non-factors like Swansea City have been able to replicate van Gaal’s old control-obsessed playing style. On the European stage, recent Barcelona and Bayern Munich teams have not only done similar but married that control with other aspects (high pressing, for example) that increase its effectiveness. Quite simply, there are now other managers who can perform van Gaal’s best trick, and many of the ones who can’t at least now know how to counter it.

For some, Rafa Benítez is a fraud who isn’t nearly as good as the jobs he’s gotten would lead you to believe. But it should be remembered how differently he was viewed at Valencia, and even during his early years at Liverpool. Benítez is now seen as a functional (at best) coach, but he introduced a more attacking approach to the (admittedly already good) Valencia team that he inherited. At Liverpool, he inspired a wildly under-qualified motley crew to an unlikely European triumph. His use of the double midfield pivot at that time may not have been unique, but he was unquestionably one of its most notable proponents. These days, even the average relegation fodder team has the personnel to play a 4-2-3-1 formation, and the tactical acumen to match up against it. Benítez has stalled, and is now on his third job (after Inter and Napoli) which he arguably was only handed because of a now outdated resume. After a sustained period of relative success that he has so far been unable to replicate, Benítez — like Wenger and van Gaal — may just be past his best.

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The latest and perhaps greatest of these active managers to find himself being compared unfavorably to a past version of himself is none other than José Mourinho. There is a cruel irony that the defeat against Leicester City is the one that condemned Mourinho to the sack. Here is a team that tops the table, that is compact, physical, able to withstand pressure, and then attack ruthlessly on the counter; the very same sort of model with which Mourinho enjoyed so much success during his first spell at Chelsea.

Mourinho is still young, but he’s now into his second decade as a manager, and circumstances seem to have changed him. The Chelsea team of 2015 is not the team of 2005 – this version needs serious retooling, a skill which Mourinho has yet to demonstrate. But this is not the Mourinho of 2005, either. He has in some ways, become a parody of his best self: more paranoid than mischievous; more divisive than magnetic. A new environment may yet revitalize him, but it’s clear as day that this Mourinho was not up to this particular challenge. Mourinho is without question one of the greatest managers in history, but time and changing circumstances catch up to even the very best. The likes of Ferguson and maybe Ancelotti are the exception, but the examples of Guus Hiddink, Fabio Capello, Wenger, van Gaal, and Benítez prove the rule.

There are no secrets in soccer management anymore. There will always be times when true visionaries emerge, but in almost every case the rest of the field eventually catches up. When that happens, managers face a new challenge: surpassing their own innovations. Once or twice in a generation, there will be a gifted manager who also has the ability to continuously evolve and to stay at the leading edge of the sport. But for most, even the special ones find themselves surpassed; persisting on a reputation that they no longer deserve.