"In two-and-a-half years they find themselves going from a mid-table Premier League side to being bottom of the Championship and in dire trouble at the moment," said Curbishley.
Curbishley has since managed West Ham United but is currently out of work.
And although he admitted he was looking to get back into management, he said his wish was to manage in the Premier League and had no plans to return to The Valley.
"I left the club when Iain [Dowie] went in there," he said. "I think I left them in good shape, they had the opportunity to bring players in.
"I've only been back once. I felt that I'd been there so long and I should leave the new manager to get on with it. I kept well away."
Although Charlton appear in grave danger of relegation to League One, Curbishley insisted that relegation was not a certainty yet.
"When I first went to Charlton as a player we stayed up by one point and the next season we got promotion," he added.
"It can be done but they've got to start winning games and putting three or four results together very quickly."
Bookmark with:
What are these?