Departing coach Duncan Fletcher insists the foundations have been laid for England to be a successful side.
Fletcher ended his eight-year reign with one final news conference
He revealed he had offered to help them through the summer, but Peter Moores was named as his successor immediately.
"If you look around we are the youngest side in the world in Test cricket - not only in caps and ages, but also in inexperience," Fletcher said.
"We've shown the way we can play on occasions, we just haven't put it together on a consistent basis."
Fletcher announced his decision to quit before England's final World Cup game on Saturday, which was a thrilling one-wicket victory over West Indies.
He added: "I have said previously that this World Cup was a bit early for them and it could take up to a year, but who knows?
I'd made up my mind early on the qualifying stages that I wanted to finish at the end of the World Cup
"They could suddenly put it together in six months, but I would still be a little bit patient with them because they've got a bit of learning to do.
"The foundations are there, but I think it might take a little bit longer."
Fletcher decided to resign during the group stages, and had informed John Carr, the England and Wales Cricket Board's director of cricket operations, before their win against Bangladesh on 11 April.
He offered to stay on to stay for the summer, but the ECB preferred to make a clean break and appoint former academy director Moores.
"I'd made up my mind early on the qualifying stages that I wanted to finish at the end of the World Cup," said Fletcher.
"I wanted to go for personal reasons. I didn't know what I was going to do after that, it was really up to the ECB to decide what they wanted to do.
"I enjoyed the job and I still thought I had other things to offer, but I'm sure there will be other things out there.
"I need a break for a month or so and then I'm sure my wife will be trying to kick me out of the house."
Asked how he believed he had fared in the post, Fletcher added: "It's difficult to say, but from my point of view it's been pretty good.
"One thing you can say is that when I got the job not many people wanted it but now everyone is clamouring for it so that's a pretty good indication."