I don't want any player who'd try harder under a different manager.
As much as we want Wenger out, some of the players lack of effort is a disgrace.
We've got so many shite players.
As much as I'd like to agree with you on this, this is the nature of teams. Football teams is an extreme case, but the same applies across sport and businesses. If the leader doesn't have a vision that the team can sign up to and believe in, if the team doesn't believe in them as a person, then the leader won't be able to motivate well enough and it's inevitable that people will lose focus and won't put in full effort.
In elite sport it's a lot more obvious, because the margins are so small. So if 1 premier league team is 99% motivated and another is 98% motivated it will be obvious when they play each other. But can you honestly say that we've always been fully committed to our work when we've had a boss who we don't like or who we think is not competent? I definitely have had periods where I haven't been fully motivated in my work and my productivity clearly drops.
And don't say that they should be held to a different standard because they get paid so much. Money is an extrinsic motivator rather than an intrinsic one. The amount of money is irrelevant, for a player the money they earn is only about recognition and status. So the absolute amount of money is not what is important, it's the relative amount of money compared to other footballers. And no matter how much a person earns, other factors will always be more important to their motivation levels.
Ultimately, it's the job of "Managers" or "Leaders" (in any organisation, whether that's a sports team, business or government) to get the best out of their teams/employees/workers.
If it was 1 player who wasn't performing then that player needs to up their game or be moved on. When it's pretty much every player in the squad who is underperforming, then it's the manager who has to take the responsibility for the collective lack of effort.