Roy Hodgson believes Crystal Palace would need "an enormous amount of investment" to achieve more than regular Premier League safety.
The 73-year-old reached the milestone of 350 games managed in the Premier League, becoming only the 10th coach to do so, and has been at Selhurst Park since 2017.
The Eagles are currently 14th in the Premier League, and a win at Brighton on Monday would see them match Palace's best ever points tally after 25 matches, but Hodgson has come under fire for his side's recent performances.
Although they had appeared to have regained their early-season form with victories against Wolves and Newcastle, Palace have slipped to defeats to Leeds and Burnley since then.
"I do think it is difficult and important for clubs (just staying up)," Hodgson said.
"People need to be careful. When Alan Curbishley left Charlton many years ago, they were constantly in the top half of the table. It was because fans were not happy and thought that finishing in the top half of the Premiership wasn't enough and that they needed to kick on.
"They did, they kicked downwards and that is the only problem. You have to be careful. This is part and parcel of our football life.
"As a manager and coach or player you're going to be criticised for performances and people are going to read into things from performances that are not always there. As owners, you're also going to face a lot of criticism from time to time.
"The so-called 'lack of ambition', whatever that happens to be – it covers a multitude of sins. These are topics and issues that are going to be raised every time you have a spell which is not living up to people's expectations or hopes really.
"Personally I think it is not a bad achievement for a team that has actually spent not very much money and has worked within a reasonable budget to be in the League every year.
"If people want more than that then it is going to take an enormous amount of investment because these days to get yourself into that top half of the Premier League – we can see what these clubs are spending – it is going to involve a massive expenditure."
Hodgson is hoping his side can repair some of the damage done by recent performances and give supporters something to cheer about when they go to rivals Brighton on Monday night.