Okay pal, here it is; no not every marine/soldier is a knife expert. The ugly truth is, they mostly don't even care. Just like the general populace, the vast majority of servicemen don't know much about knives, don't care much about knives, and won't spend a lot on a knife. They will walk into the PX, and buy what the PX has for sale cheap.
In the ten years I was n the army combat engineers, I saw more Buck 110's on the hip than ANY other two or even three knife brands. In Vietnam, the most popular fixed blade in the field was the Buck 119 special. Both Bucks were on sale at the PX so that is why most swinging Richards had on their hip. Contrary to what some knife makers would have you believe, there was no Randall's, or other customs floating around. I saw one single Randall knife the whole tour I was in Vietnam, and that was on a markedly over weight supply sergeant of the chairborne ranger class.
By the time you've served/survived one "deployment" you know what's gong on and what you need.
So Gideons, what branch of the service did you serve if any, and what was your experience?