Sir Alex Ferguson has labelled the management game "an unfair industry".
Former Manchester United skipper Roy Keane became the latest casualty yesterday when he was axed by Ipswich and on Sunday, Ferguson's side can effectively sound the death-knell on Roy Hodgson's time as Liverpool boss by beating the Merseysiders in the FA Cup.
And with Avram Grant, Carlo Ancelotti and Gerard Houllier under pressure at West Ham, Chelsea and Aston Villa respectively, Ferguson told Key 103: "It is an unfair industry now. Managers don't get the time to introduce their own philosophy or change trends, which were the reasons for giving them the job in the first place."
He added: "When Liverpool chose Roy Hodgson, they did it on the back of his great experience at different clubs.
"But we are in a results industry. If you get a few bad results that can happen.
"I can't explain it and I don't think there is any point trying. Anyone who has any common sense understands the kind of football we have nowadays and the kind of pressure we are put under."
Apart from the odd exception; Ferguson at United, Arsene Wenger at Arsenal and David Moyes at Everton, the shelf-life of the men in the hotseat is getting markedly shorter.
The assessment time is now done over a period of months rather than years and Ferguson is not sure the new breed of owners are fully in tune with the best way to do the job.
"I don't think they have the stable directorship that they used to have when the father and the grandfather were chairmen for 30 years," Ferguson told Sirius XM.
"You have new owners. You have people from abroad; the Middle East, the United States. It is a different culture. They don't have the same patience as older generations."