Nah ... My both my gramps were gone before the 110 folding hunter came out. My (maternal) great gramps (1882-1973) only carried slipjoints.
My pop's was weird. He didn't carry a knife at all, except for a Rapalla filet knife in his tackle box. He might have had a company issued Stanley box cutter in his locker at work. (I don't know if the blade retracted, or know for sure if he even had one.)
I got my first 110 around 1968 or 1969. Most of my Jr. High and High School classmates had one on their belts, too. Especially in the High School shops classes.
How can they still be a "hot commodity "? Easy. They are affordable, strong, rugged, hold an edge long enough to skin and gut at least three whitetail, or scrap who knows how many head gaskets and cut I don't know how many heater and radiator hose before needing the edge touched up. They can also whittle tent stakes, cut what's needed for a shelter, clean fish, cut fishing line and anchor line ... and whittle a spoon ...
In short, they do what you'd need a knife for at work or our in the boonies and sticks, and they don't get in the way when carried in the sheath. Oh, they also feel better in hand than the boxy "modern" knives do, and don't have any clip caused hot spots. (at least they feel better than a boxy modern, in my hand.)