West Ham boss Sam Allardyce feels managers are losing their jobs because of the need for instant success in football.
Allardyce is now the only manager in place at the six clubs who were either relegated from, or promoted to, the Premier League last season.
"From a manager's point of view it is always sad when you see one of your fellow managers lose their job," he said.
"We all know it is a volatile world and we know how volatile it is year-in, year-out now and it is becoming less patient than ever before.
"He (McDermott) did a fantastic job at Reading and at this particular time the owner thinks bringing someone else in for the last nine games is going to make the difference, which is pretty sad really.
"Everybody strives for success and at the end of the day there are only three teams can get promoted.
"Realisation and expectation don't go together, realisation is, if you have got a small wage budget you are going to finish lower in the league.
"New owners, if they are foreign or British, they are less patient than ever before and generally a sacking comes from poor results, media and fan pressure and the owners are unable to deal with that pressure like the managers can."