Pierce was traded to the Nets from the Boston Celtics in June 2013, but as the time progressed he slowly started feeling more and more frustrated.
Pierce also pointed out that many of the players lacked passion for the sport and never had the urge to practice.
"It was just the guys' attitudes there. It wasn't like we were surrounded by a bunch of young guys," he told ESPN. "They were vets who didn't want to play and didn't want to practice. I was looking around saying, 'What's this?' Kevin Garnett and I had to pick them up every day in practice.
"If me and Kevin weren't there, that team would have folded up. That team would have packed it in. We kept them going each and every day."
The 37-year-old also lashed out at Brooklyn point guard Deron Williams for shying away from the challenge of being an MVP contender. Pierce admitted that he always thought Williams had the ability to be MVP, but added that the 30-year-old "just didn't want that".
"Before I got there, I looked at Deron as an MVP candidate," Pierce said. "But I felt once we got there, that's not what he wanted to be. He just didn't want that.
"I think a lot of the pressure got to him sometimes. This was his first time in the national spotlight. The media in Utah is not the same as the media in New York, so that can wear on some people. I think it really affected him."
When Williams had failed to live up to his expectations, Pierce looked to shooting guard Joe Johnson as a potential leader.
However, to his disappointment, Johnson preferred keeping his head down and did not relish being the centre of attention.
"Joe is quiet. He doesn't want much attention. He doesn't say much," Pierce said. "There's a lot of secondary guys on that team. KG and I went there looking at them as the main guys who would push us, because we were advancing in years. But we ended up doing all the pushing."