Michael Clarke fears the Australian team have some tough times ahead after the retirement of stalwarts Shane Warne, Glenn McGrath, Justin Langer and Damien Martyn.
Clarke told the Herald Sun the world champions won't be as dominant as they were the past two decades.
"I think the Australian public has taken the Australian cricket team's form for granted because we have had so many great players and they have performed so good for 10-15 years," Clarke said.
"I think it is unrealistic now and I think that has shown recently.
"We didn't win the Twenty20 World Cup. We only won 4-2 in the Indian one-day series and that was a tough series.
"I hope we win every game we play, but the reality is it can't happen."
Australia have dominated world cricket in recent times, whitewashing England 5-0 in the Ashes and winning the World Cup for a third consecutive time in the Caribbean earlier this year.
However, Clarke expects a difficult summer against Sri Lanka and India.
"We have two very strong teams coming here and we have to give credit to other sides in the world who are playing very good cricket," the 26-year-old said.
"I believe it's going to be very different this summer to past summers. It's going to be very tough."