Do you for any reason believe the liners of the liner lock knives are a different composition or hardness than the compression lock liners? Do you also have any reason to think the contact area of the compression lock is less than the liner? Have you measured the radiused lock surface on the tang of either design? How did you apply shear stree to the compression lock? How would that stress not have been applied to a liner lock?
I have had liner and frame locks with premature and rapid wear. It had absolutely no correlation to sharpening wear. I have had rapid wear with steel and titanium liners. Individual examples of any lock may have poor fit or material quality issues. How premature was the premature wear? I have had lockup depth change ~30% in a week with liner locks. Others had had no perceptible change over years.
Q: Do you for any reason believe the liners of the liner lock knives are a different composition or hardness than the compression lock liners?
A: Hardness of either lock mechanism piece is probably about the same. I don't know, nor do I care. In the case of the liner lock it is irrelevant since the lock face is larger, and force is therefore distributed over a larger area preventing localized deformations that lead to the blade rocking that I saw on a compression lock knife. Even if the liner lock focused all of the lock's restraint onto a single point (think CRK Umnumzaan's ceramic ball), I would still maintain that a point-loaded liner lock would be succeptible to less blade play than the knife with the compression lock.
Q: Do you also have any reason to think the contact area of the compression lock is less than the liner? Have you measured the radiused lock surface on the tang of either design?
A: I've held them up side by side, and can say without a doubt that there is more metal holding the liner lock Military open than any compression locked knife I've owned (PM1 & PM2). I shouldn't have to measure the contact area when there is such an obvious difference.
Q: How did you apply shear stress to the compression lock?
A: As a whole, the bulk of the lock bar/tab is under compressive loading. However, the corner of the inside face of the lock bar undergoes localized shear stress as it engages with the ramped tang and is held in place by the stop pin.
Q: How would that stress not have been applied to a liner lock?
A: There is the same type of shear stress applied to the inside corner of the liner lock bar as it is the first portion of the lock bar to engage with the tang. The bulk stress, though is also compressive in nature.
Q: How premature was the premature wear?
A: I used the knife for fiddly EDC cutting for six months. Never had the need/chance to sharpen it before the blade play got so annoying that I decommissioned the knife.
I am not equating actual sharpening with lock wear. What I am saying is that if the lock shows signs of pooping out before I've had a chance to get some use out of the knife then the overall design needs improvement. Of course different manufacturers' liner locks and frame locks are going to wear in differently. That's not the point I was initially trying to make, however it does illustrate my original opinion, which is to say that a worn-in liner lock will lock up tighter over the life of the knife than a worn-in compression lock. Add to that the fact that liner locks are easier to manufacture, and can be made into very robust mechanisms (e.g. Spyderco Gayle Bradley & PPT, or Emersons, among others), I can see why it is such a popular type of lock mechanism.
-nate
