This is such a stupid argument. Haven't you learned anything from decades of watching football? Players don't just stop trying. They don't just think **** it, I can't be arsed any more.
It is ALWAYS how they are led. It is ALWAYS on the manager.
How many times have you seen players being completely lost and a new manager comes in and they look a different player? It's about how they are managed and led.
Players play. That's what they are paid to do. They are trained not to think. They do what they're told. When they lose faith or simply cannot understand or enact the instructions they're given, it is ALWAYS on the manager.
When some dipshits on here were saying the same in the late days of Puel, they soon shut up about certain players as soon as he went and a new manager came in. e,g, "Vardy was finished" and suddenly he was back.