It also takes a lot to destroy what he builds. All a club would need is to build upon what he left them with and they'd continue to thrive. Barcelona won the league the season after his departure with a record points tally with their manager the late Tito spending a lot of the time in the hospital. I could only think of Pep, Klopp, and maybe Tuchel in the future who could do something like that, which is building a team that could actually still win titles on autopilot.
At City, Pep went from having one of the oldest squads in the league to have one of the youngest, while remaining in the title picture. On the other hand, we saw how good Sir Alex was when he won the last MU league title with a team in his last breath. Just different kinds of great.