The people are badly under exposed because of the bright background. Fill flash should have been used to balance the exposure of them to the background.
With the right flash unit and exposure settings the background could have been made darker than the people.
I bet the camera used Evaluative/Matrix light metering mode.
Spot metering mode and metering for the people would be another approach but he background would be solid white (blown out)
Center-weighted metering might have worked.
JPEG files have limited, if any, editing headroom.