The team is not necessarily his because he chose the players or signed them, they become his when he has had them long enough to impose his ways and methods on them.
Has he had them long enough? Most of them, yes. The new players, maybe not. However, his current record, this year, just isn’t good enough. The club have got rid of players that he’d worked with for a while (so knew his methods).
Ultimately, either the players aren’t good enough, or he isn’t. We can change the manager, we can’t change the whole playing staff.