The public got bored by the third moon landing. They would rather see reruns of I Love Lucy.
Because what they saw was some guys speaking in what to them was scientific gibberish and video of hours and hours of core drilling, cable unwinding, and rock collection. Even today the most diehard NASA fans cannot bring themselves to sit through all 6 DVDs of the Apollo 16 lunar EVA. It's too boring. Lone among the astronauts, Al Shepard thought the science secondary to the exploration and was ostracized for it. Even today the best two video clips from the lunar exploration are the 16mm films of the rover cutting donuts in the lunar soil, and the camera attached to the front of the rover as it traversed some small hills from the POV of the astronauts.