Does your problem is that he doesn't stay for + 4 years at a single club ?
Because I don't give a shit about that as long as he wins trophies here and will leave a solid team for his successor regardless.
Which guess what ? Is what happened in his previous 3 clubs, won trophies and left behind a solid team that kept on winning.
Since when any team hire a manager on the basis of him staying +4 or 5 years anyway ?
The Chelsea side he left won EL and finished 3rd the next season with Sarri, they didn't need a rebuild or a reset. He left inter due to problems with the transfers, after winning the league and now Inter are as good as they were under him last season, and Juve kept on dominating the league for several years after he left them.
So yeah, there's nothing "short term" about the teams he managed. Just because he himself didn't stay for 5 years doesn't mean his clubs collapse once he leaves.
Time for us to start acting as a proper big club and hire managers for the fecking present first. The current team is an elite and most of them are actually not that young. De Gea 30, Shaw 26, Maguire 28, Varane 28, Pogba 28, Ronaldo 36, Bruno 27, Cavani 34, even Rashford is 24 now. Most of the squad's best players are in their prime already, or approaching the last half of their career. It's time for us to actually win something with them, because 4 years from now on we'll start thinking about replacing the likes of Varane, Maguire and Bruno. Pogba might be leaving soon as well.