Palace meet Tottenham on Sunday yet to win in the Premier League this season.
Glasner said: “We were 10th last season and now to improve? Read the table. Ninth I think was West Ham who invested £140m net, eighth was Manchester United and seventh was Newcastle.
“So to improve we have to overtake one of them and when we look back, Fulham was 13th or something, investing £50m net and Brighton were 11th investing £180m net. These are the surroundings of us, we saved £20m net.”
Asked if he is frustrated with the lack of spending, Glasner replied: “It’s not a public discussion. I’ve already mentioned it several times before: we could have done better in the transfer window.
“With four signings on deadline day, it’s not how you wished a transfer window would work. No one says: ‘Yes, we will wait until deadline day and then sign four players two weeks after the Premier League has started and without (the signings having) any pre-season'.
“This is clearly what we should have done better. But in the end it was the club’s decision. We all expected a lot from this season. It hurts; maybe we lost a sense of realism.”