The front pin may get some wear if the bearing freezes up but I'm guessing that's pretty rare?
The trunion pin (shaft) is to the rear of that pin & bearing. The trunion carrier is what allows the turntable and axle to rock from side to side. If that shaft wasn't greased religiously, wear would cause the entire front end to progressively feel more 'sloppy' since it is literally the one point holding the front end assembly to the frame.
