Ferguson always carried some older players but they were not always the bedrock of their side. His final team though in 2012/13 was the one where he showed his ability to eek out massive performances from his aging and well past it squad. But for the most part usually his key players were younger certainly in his teams.
Just look at our starting 11 against both City and Fulham in the Charity Shield and first league game. Matip, Alisson, Van Dijk, Thiago, Henderson, Fabinho, Salah and Firmino all started. 8 players there and at the time 7 of those 30 or above. Thats not a good way to transition the team.