As the old quotation goes, “economists correctly predicted nine of the last four recessions.”
One problem is undefined complexity. Some of the world markets and societies actions as so subtle or unexpected that even the best economists can’t include them. This causes economic forcasts to be about as accurate as long term weather forecasts.
Another problem is that many of the most quoted “economists” have some biases and work for institutions with a particular view so they tilt their statements toward their desires and often away from reality.