Categorizing Ten Hag as one of the worst coaches for Manchester United may not be accurate, but I don't think Ten Hag is one of the most successful. Ten Hag had an incredible season last season with Manchester United, as a result Ten Hag managed to get Manchester United through to the group stage of the Champions League this season. But not so in his second season, he failed to live up to many expectations and his team fell apart.
Until tomorrow and beyond, money doesn't guarantee everything is fine for the club. PSG has spent a lot of money to win the Champions League title, yet they still failed despite reaching the final a few seasons ago. Manchester United needed big changes including getting the club acquired by new investors, but that still failed when the Glazer family still refused to do so.