''Any successor to our current manager may not be as successful,'' the club's American owners warned potential investors in 2012, a year before Ferguson's sudden retirement after delivering 38 titles.
With David Moyes not even completing a full season in charge, what an understatement that now seems. United's first managerial transition since 1986 has been a calamity, with unwanted records set and mounting disillusionment where once the club was the byword for stability in the mad world of football.
This time United won't be entrusting Ferguson with hand-picking his successor. Ferguson was allowed to overlook more accomplished candidates on continental Europe with resumes befitting a club of United's stature, and turning to a fellow Scotsman who didn't win a major trophy in 11 years at Everton.
''His appointment is a victory for common sense and stability,'' the club trumpeted at the time. ''United are in safe hands.''
But Moyes couldn't grasp the biggest job in English football, it quickly transpired. Even with a six-year deal, Moyes was constantly on edge as a side that ran away with a 20th English title by 11 points in Ferguson's final season went into freefall.
Out of his depth tactically and looking increasingly haunted, Moyes was not backed publicly once by the club. Vice chairman Ed Woodward, blamed by many fans along with Moyes for the club's failure to strengthen the squad after he assumed transfer responsibilities last summer, maintained a noticeable silence as discontent grew. United became an object of ridicule, particularly over Moyes' increasingly far-fetched assertions of his team's supposed strengths after losses.
Old Trafford was a fortress under Ferguson's command, but six teams have won there this season in the league.
Ferguson's mission after taking charge in 1986 was to knock Liverpool ''off their perch.'' He succeeded, with United's 13 championship successes under his tenure taking the club past Liverpool's record 18 to 20. How galling must it be for Ferguson to now see Liverpool on the brink of its first title since 1990, 23 points in front of United
It was a second loss of the season to Everton on Sunday that convinced the Glazers to put Moyes out of his misery. Even more galling for Moyes is seeing the Merseyside club he left for a supposed upgrade on the managerial ladder sitting in fifth, 12 points and two places ahead of United, which was disjointed and lacked direction under his command.
One direction the team isn't headed is across the English Channel to Europe for top-level competitive matches. Moyes' last salvation this season was winning the Champions League but, after limping through past Olympiakos, United exited in the quarterfinals against Bayern Munich. Humiliating for a team that has qualified for the Champions League through the Premier League every season since 1995, United might not even make the cut for the unloved junior competition - the Europa League.
Just as significant as the loss of tens of millions of dollars of UEFA revenue is the damage to the club's prestige. And this is a club that claims to have 659 million followers, or 1 in 10 inhabitants of the planet. One family follows United with no apparent affection beyond the ability to generate cash from the club - the Glazers, who have infuriated many fans throughout their nine years as owners.
Far more troubling for fans than the Glazers' lack of engagement since 2005 is the toxic issue of the club's debt that was nonexistent before the owners of the NFL's Tampa Bay Buccaneers saw the opportunity to squeeze cash out of English football's biggest club. More than $1.1 billion has been drained out of Old Trafford by the Glazers to service a debt that five years ago reached 716.5 million pounds (then $1.1 billion) and has now been halved.
''The problems lie a lot deeper than David Moyes,'' said Sean Bones of the Manchester United Supporters' Trust. ''They lie with the Glazers and how they run the club.''
Fans can only dream about the playing talent $1.1 billion could have bought. But with cash available to reinforce the squad, Woodward met the scouting team on Tuesday to assess transfer targets even before Moyes' successor is hired.
Ferguson's ability to deliver trophies helped to largely suppress a mutinous atmosphere at the 136-year-old club that was taken public on the New York Stock Exchange in 2012. Wall Street investors welcomed the dismissal of Moyes, with shares rising more than six percent in Tuesday morning trading to $18.84 - the highest since Ferguson's retirement last May.
Although some supporters might hope the Glazers follow Moyes out of Old Trafford, with the club valued at more than $3 billion and set to generate in excess of $700 million this season alone that seems unlikely. By promoting Ryan Giggs to interim manager until the end of the season, the club's most decorated player could be a unifying force for the final matches and prevent an outpouring of anti-Glazer dissent.