You are correct. The wing does have an incidence angle. However, the c of g and aircraft mass will change throughout the flight as fuel is used (swept wing aircraft) the 'deck angle' will therefore change as the angle of attack alters to compensate for altitude, airspeed, and lift requirement. There is also the fact that the fuselage adds to the total lift of the aircraft and there will be a sweet spot angle for the entire aircraft to meet the airflow.
Someone clever will be along in a bit with some maths to explain.