I think cases like Ibe, Deisler, Morrison and Adriano go to show how underrated mental health is when we judge footballers. In terms of talent, these guys were phenomenal specimens but suddenly their desire to succeed is mentally compromised and just as suddenly their careers are over.
Like, most people would think that if a world class player like Adriano suddenly stopped being fully committed to the sport, he would still be an excellent player playing in a top league - just maybe a 10% drop in performance from incredible to merely very good. The fact that they could subsequently barely get game time in appalling leagues goes to show that mental health issues can undermine and destroy everything in a way that physical deterioration can't.