Not just Klopp zz. Pep, Pochetino, Koeman et all.
I'm not singling him out as he's Utd manager, just that he's the biggest name struggling the last few years, but José's general MO is becoming outdated and the game is passing that brand of football by now as these newer, younger coaches evolve at big clubs. Which is to his detriment as he's only 53, a mere 4 yrs older than Klopp. But he looks and his football feels like he's a granddad from a bygone age that just isn't ready to fully let go and move with the times. I hope for your sake the sheer weight of what Utd fans expect forces him to change on a consistent basis or you'll just get left behind. Someone is the exception to the rule right now and how long that's sustainable is open to debate.
Oh, and that's completely aside from you missing the point by a Country mile that these managers have a team structure to defending on the front foot that is every bit as effective as sitting back.
Mourinho isn't being left behind though, it is far too early to come to that prediction based on him having one bad season at Chelsea. Reality is he won PL title the season before that people so easily forget. 'His football feels like he's a grandad from a bygone age', a lot of people criticise Mourinho for his style of play, sometimes it is justified. But Mourinho is a manager who sets up his team to the opponent and sets out a gameplan. To say his style is outdated, bygone and whatever else is absurd when he has still achieved more recently than any manager you have mentioned.
Plus just look to the Burnley game, 37 shots most ever recorded in a match since Optastats introduced I believe. His style isn't outdated, it's just built for the opponent and who are we to argue?
Pocchetinno, Klopp, Koeman all good managers with different footballing perspectives, but to say they are outdating Mourinho is just not correct. When they have some profound success with it then sure but until then, it's just media bs if you ask me.