The interesting thing is that if we look at the amount of aileron deflection to balance out the prop torque it's surprisingly little. And to me that suggests that the slip stream effect on the fixed portion of the wings is indeed considerable.
Keep in mind that when the folks that wrote "Stick and Rudder" were sketching their pretty pictures that they were trying to explain why the plane wants to YAW AND TURN when in a slow airspeed climb with lots of power and why some rudder is needed. The diagrams would have been considerably different and the students highly confused if they started listing and resolving all the effects and included prop hanging with the Cessna 150....
So simplicity is good to a degree. But all too often folks can walk away with the idea that what they were taught is the WHOLE picture.