These bearings move back and forth constantly, over less than a degree of rotation, as you drive straight, which you do 99% of the time. The grease doesn't get redistributed unless you turn the wheel, and even then not much. Not an ideal situation for roller bearings, which are designed to be rotating, primarily in one direction, all the time. What you are seeing is normal, exacerbated by large tires and offroad use.
I personally use moly grease on everything just because non-moly doesn't offer any advantages, and with that in mind why bother with two types? But for trunnion bearings in particular, moly seems to be a better fit. That being said, it doesn't solve this problem either. They are a wear item. Most people don't notice how quickly they wear because the wear isn't obvious unless you disconnect the steering linkages and rotate the knuckle. As long as they are still tight and no play is felt when rocking the wheel at 6 and 12 while off the ground, I don't mess with them.
My thoughts are similar to this.
There's almost no rotation of the knuckle for the vast majority of driving at anything much faster than jogging speed. A few degrees each way.
I use Moly grease in everything, except wheel bearings.
Moly will provide dinner lube if the bearings end up just sliding, not rolling
I had a knuckle that was almost locked up. Didn't feel it while driving until it was completely toast.
I could barely rotate that individual knuckle by hand. The only time I felt it driving was when I had to drive a succession of tight hairpin turns (switchback??) that required code to fill lock on the steering both ways.