Going off on steel qualities seems, well a bit off, if I may say. This here is specifically a matter of geometry. In my idea, at least. The thickness of the blade (paramount IMO), the grind angle and the sharpening angle are the major kicks.
In my experience, which may be different than yours, I've found that steel quality and edge geometry are related.
I have 2 Case TruSharp knives: a large sodbuster (flat grind) and a fixed blade (hollow grind). On both knives, I've found that a normal 20 DPS (as created by a Lansky rod system) apex is unstable and prone to roll, particularly when cutting on a wooden cutting board or doing wood working type of cutting. I've also found these knives have a more stable edge when finished at 25 DPS. These knives behave similarly in this way despite their different blade geometries. IMO, blade geometry has nothing to do with edge stability. Edge stability depends on edge geometry and the quality of the steel. More to the point, Case's 420HC is comparatively soft, prone to roll and prone to forming a wire edge when I hone it.
The performance I experience has echos of what I read in the OPs post: good initial cutting with quick edge fade. Often, I can feel the burr of the folded wire edge and sometimes can get a few more cuts with stropping or steeling the edge. But I generally don't want to waste time with that.
In contrast, I find I can put 17 DPS edges (again, as measured by the Lansky - which introduces some error due to varying blade height) with my similarly sized Bucks and Opinels. For harder use, I put on a 17 DPS back bevel and a 20DPS micro edge. The difference I find between the Buck and Opinels compared to the Case TruSharp blades is night and day but I'm just reporting on my experience, which may be different than yours.
Regarding blade geometry (as opposed to edge geometry), I think this has a greater impact on things like the ability to throw curls when wood working, the ability to cut non-self-separating materials (e.g. potatoes, cardboard), and the ability to split wood. I'm rather unconvinced that "thinness behind the edge" matters as much as it is often described. My Opinels keep pace with Bucks, despite the Bucks being much thinner "behind the edge". I think thinness behind the edge just makes touch up sharpening easier for most people. An Opinel, like the Bucks from the 70s which had compound hollow grinds, are harder to sharpen compared to the current Buck 2000 profile because you have to remove more metal to get the same result. In short, a thin hollow grind just establishes a very high back bevel. In any event, I have a hard time seeing how the blade geometry is mattering much for this paper cutting exercise other than the fact the SAK is thinner above the cutting edge.
OP... Since you have a 110 and a #8 available, I recommend you rerun your test after giving both a good edge sharpening. I suspect what you'll find is that cutting performance differences will have more to do with which one gives you a more powerful grip (the 110 has the edge here, I'll bet).
Now run the same experiment between the Buck 110 and Opinel 8 while cubing yams or potatoes. I'll suspect you'll find the Opinel easily wins and that has everything to do with the grind. Run the experiment with an Opinel 10 if you want to rule out blade thickness as an issue. Hollow grind with sharp transition shoulders drag in difficult to separate materials like potatoes.
