Alex Ferguson would not have survived if he was starting out as Manchester United's manager today.
Football sociologist John Williams believes the pressures of the Premier League and the demand for instant results would have led to an early exit from Old Trafford.
Mr Williams, a lecturer at the University of Leicester, was speaking after the Manchester United boss stepped down after 27 years at the club.
He said: "It is not clear if it was brilliant foresight by the club or his bloody mindedness that saved him at the beginning."
It is commonly held that a winning goal by former Foxes player Mark Robins in a cup tie at Nottingham Forest on January 7, 1990 saved him.
The under-pressure manager was in danger of being sacked had United lost and gone out of the Cup, as they were 15th in the league and had already been eliminated from the Football League Cup.
However United went on to win the cup that year and set the pattern for Sir Alex's years of unrivalled success.
Mr Williams added: "The pressures in the Premiership now are much greater than in those days.
"It is unlikely that a manager would last more than five years in any event. They would either be sacked or would want to move on."
But Mr Williams added: "Over the years he has shown an ability to put fear into players while getting them to play for him.
"He also refused to allow players to dictate to him and he knew when it was the time for a player to move on.
"He could spot and develop talent but he also had luck. He inherited a youth team containing David Beckham, Paul Scholes , Ryan Giggs and the Neville brothers.
"His only true howler was signing Juan Veron for £28m in 2001."
Mr Williams, a Liverpool supporter, said: "The only downside is that I don't think he was as successful in Europe as he could have been. United being the richest club in the world at the time should have won more than two Champions League titles."
De Montfort University's Dr Neil Carter, author of the first academic history of football manager, said Sir Alex is "the most driven individual in the history of football".
Dr Carter, of DMU's Centre for Sports History, said Ferguson's management style had now become the norm for many Premier League managers keen to emulate his success.
"Football management is about four key areas – judgement of players, tactical acumen, motivational skills and dealing with the media," he said.
"Ferguson showed that there was no room for sentiment in his dealings with players. He was happy to move on players like Beckham, Jaap Stam, Ruud Van Nistelrooy.
"He brought in some key players like Roy Keane and Eric Cantona but when he thought their use was coming to an end, he had no qualms about selling them.
"He's got tactical nous, as we saw in the '99 European Cup Final when he brought on Sheringham and Solskjaer. Man Utd have always played an attractive, forward-thinking game and Fergie has continued that tradition."
Dr Carter also described Sir Alex's legendary "hairdryer treatment".
"He has motivated them and this style of motivation has fed through football," he said.
"As managers want to model success, so they draw on that model, a very kind of authoritarian, autocratic style. As much as he plays the players, he plays the press – he has admitted to "banning a few journalists now and again" to keep them in line.
"He uses the press as a man management tool. Look at when he humiliated David Beckham in public when he did not turn up for training. He told the press Beckham was not being truthful, dropped him for the Leeds game and then made him sit in the stands.
"He's shown a passion for the game, no individual in the history of the game has ever been so driven. I think he will miss the day to day contact, the hands-on running of the team.
"When people come to research the history of the game, they will see how Man United's period of success co-incides with the birth of the Premier League, and the commercialisation of the game. United have capitalised on that in way other clubs haven't. And they have been able to do that, to a large extent, because of Sir Alex Ferguson."
The Fox fanzine editor Gary Silke said: "We will not see the like of Sir Alex Ferguson again. I don't think a manager would be given the time to get his team playing as he was. He got a life-line because of the success in the FA Cup because that was much more thought of then than it is now.
"I think that David Moyes of Everton is likely to be appointed as he has refused to sign a new contract with Everton. However I do not think it would be trouble free with Sir Alex likely as he is likely to be in an office down the corridor."
Mr Silke interviewed former City manager Frank O'Farrell who succeeded the legendary Sir Matt Busby at United in the early 1970s.
He said: "Frank said that he was always aware of Sir Matt who had a bigger office than he did. It was not a success and I think David Moyes could be in a similar situation."
He added: "There is talk of Mourinho but I believe he is too far down the road with Chelsea."
Former City boss Martin O'Neill, once tipped as a natural successor to Sir Alex is not in the running.
Mr Silke added: "Perhaps five years ago it would have been a likelihood, but not now."
Former City and United boss Frank O'Farrell did not want to talk about the conditions the successor to Sir Alex would have to endure.
He had a turbulent time in the shadow of Sir Matt Busby.
Mr O'Farrell, speaking while on holiday in Ireland, said: "I have said all I am going to say about that. I am so glad that I am out of it all."
* Sir Alex's record against Leicester City is very impressive with United beating the Foxes 2-0 a few weeks after he took over in November 1986.
Since that fixture United have won 13, drawn four and lost only two matches against City. The last City victory was in 1998.
Ferguson, 71, has won 38 trophies in total since taking over from Ron Atkinson on 6 November 1986, including winning this season's Premier League.
He is the most successful manager in British football history having won 38 trophies including 13 Premier Leagues, five FA Cups and two European Champions Leagues.
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