Sir Alex Ferguson is undoubtedly the most successful British manager in the history of football but to correct what you said, he helped Manchester United to win 13 English Premier League titles bit the 32 you said in your post.
Since he retired from being a professional football manager, Manchester United are yet to get a manager who can be as effective as the Scot man. While he was about to leave the club, he influenced the club's management to hire David Moyes as his replacement but unfortunately for his compatriot, he didn't have a successful spell as the club manager and was subsequently sacked. Manchester United needs to get a manager who will be as good as the Ferguson in other to return back to as one if the strongest teams in Europe once again
Sir Alex Ferguson is a tough act to follow. That is without exception doomed to fail if a coach would ever try to copy a career like that of Sir Alex Ferguson because as I said before, one of the biggest problems is that times have changed significantly. He is beyond doubt a historic figure in football for many good reasons, but I am really not sure whether he could have done the same with Manchester United in these ages. Since investors joined the stages there is way more fluctuation of players and several more highly competitive addresses in football. But I like it when a coach spends more than just a few years at one club.