The credit crunch came as a massive surprise to the vast majority of people. For years, the newspapers had sung the praises of the new economy of low interest rates and they predicted continued growth for many years to come.
But actually, economists DID predict the credit crunch. It was newspapers and the Governments that failed to predict the credit crunch. Economists had been warning of the problems of keeping interest rates too low for too long for several years before the credit crunch happened, but it fell on deaf ears.
Economists don't publish their forecasts in newspapers. They publish their forecasts in academic papers. So only people who are really interested in economics tend to read them.
Such as economics editors of newspapers (who ignored them because they didn't want to devalue the houses they lived in by worrying the population, and because warning of house prices falling doesn't sell newspapers very well to the middle class, middle aged homeowners who usually buy their newspapers).
Also such as Governments, who ignored the warnings because it didn't fit with their "new economy" belief system, and because keeping interest rates low kept people voting for them, but avoiding or minimising a future recession doesn't win any votes.
But economists don't get everything right. It's not a science. Economists disagree about things. And forming a consensus of economists is difficult.
However, with Brexit, this is completely reversed.
There is not a single economic model that suggests anything other than a long term hit to the UK economy as a direct result of leaving the EU.
Actually, these are economic models. You effectively just put the numbers in and out come the negative results from the mathematical equations.
There isn't a single peer-reviewed economic paper predicting anything other than a significant negative economic impact from Brexit.