In this day and age it is about coaching, old school managers are a thing of the past. It is about improving players individually, so they fulfil their potential. Above all it is about coaching your players so that the whole of your team is greater than the sum of the parts.
Carlo isn't a coach, he is an old school motivator who now works under a Dof.
Carlo was successful in an era of old-fashioned managers. In an era of coaches he has relied on the likes of Clement who has been an abject failure at Derby, Swansea and Reading as a manager was Carlo's pick as first team coach. We now have Dunc and Carlo's lad coaching Everton.
Carlo comes in wows players with his reputation and personality and initially does well. Then the lack of coaching and fitness work catches up with his teams.
It isn't about the lack of quality in the squad it is about the lack of quality in the coaching department.