Ferguson admits he is baffled by the trigger-happy chairmen of Premier League rivals.
"For 26 years I have marked every area of the training centre with my presence, my demands," he explained.
"Clubs change manager too often and this empowers players and the dressing room. This is very dangerous.
"Giggs and Scholes were not even 14 when they arrived here. It is easy at that age to nurture them.
"You're the one who gave them a chance, who is taking them where they dream of going and taking care of them. That matters."