Just because you have the players and personnel doesn't mean that any half wit with a brain can run it and optimize it as a team.
Real Madrid have always had a great set of players, but they didn't perform for years until Mourinho took over.
The Brazillian national team has always had the best set of players (until recently) but they've underachieved on numerous occasions. the Portuguese national team is another prime example. It's shocking that they haven't won a major trophy in however many years with the players that they've had at their disposal.

