The 47-year-old, who was officially unveiled as the Blades' new boss on Wednesday, claims that early rewards in football are making players less motivated.
"We always try to play good football," he told reporters when asked about his playing style. "Anyone who has seen Derby play over the last two or so seasons would know that.
"We like young, vibrant and energetic players who are hungry. Believe it or not, there are not many who are like that – they are becoming less and less.
"I think [hungry players are] on the wane because of the rewards in football that they get so quickly now."
United are currently 21st in League One with nine points from 13 matches.