Much of the benefit in the case of large hollow ground knives is "classic appeal" in that many of the large fixed blades of the 50s and 60s were thick hollow grinds, and there's just an aesthetic to them that reminds some of us of knives we admired when our interest in slicey things was first piqued.
Now of course, the knives of that era were not hollow ground for performance but because it was a comparatively easy way to grind knives (stone wheels cut steel faster than sanding belts) and cost effective for manufacture. Also, while big knives were popular because--let's face it--they're cool and they always have been, the actual NEED for them had largely gone out of the average person's life with the arrival of the 20th century. Unfortunate though it was, industrialization and urban living had removed most people from having to gather wood for fire or shelter, process bison for meat and fur, or scalp anyone. Lack of use breeds lack of expertise, and the simple fact is that there weren't enough people really using the things for anything more than looking at, wearing on their belts while hiking or watching John Wayne movies to find out that they don't work as well as some other grinds----something that a mountain man could have told them after about fifteen seconds of use. As cutting competitions, "survival" camping and just general user information became more prevalent, you saw a shift back to flat and convex grinds by custom makers, and production almost always follows custom.
Still---maximum efficiency may not stir the soul all on its own. The swoops and curves of a deep hollow grind are just sexy. I remember a gal I dated for a very short amount of time who was childish, largely self-centered, not very bright and in short not "the one" but damn could she fill out a bathing suit! Similar situation here---there are a LOT better fixed blade designs than a Buck General but I still have a couple, and occasionally head out into the woods with one, just because I like 'em.
Now, if you were using a knife as a pure slicing or scraping tool (not a likely fate for the average Busse but just saying) then a deep hollow grind does give longer blade life (not better performance, longer life) because you can sharpen and sharpen and sharpen the edge way up into the height of the blade without significantly changing the geometry of the edge and edge shoulder, but still have a very rigid blade because of the thick spine. This is why almost all straight razors have this type of grind--so that very precise geometry can be maintained for precision work, and yet the blade doesn't flex.
Full flat grinds are next in line in terms of this advantage, then convex grinds and saber-flat or saber-convex bringing up the rear. However, all of these other grinds--if you're maintaining the same edge angle--will eventually create wider and wider edge bevels as material is removed and the edge climbs higher into the primary grinds, which reduces cutting efficiency and also greatly increases the time required to sharpen the knife. This can be corrected via regrinding the primary bevels and gradually reducing the cross section of the blade, but doing so requires either power tools or more patience than most people have. This is an issue that only surfaces after a great deal of use (or a lot of excessive sharpening) but I have several old kitchen knives and even an old Kabar that I've inherited where half or more of the original blade height has been ground away, so it's not entirely a non-issue.
One last thing to bring up is that a hollow grind is not just a hollow grind, any more than a corvette is a crown victoria just because they're both cars. Some hollow grinds are done on wheels so large than you just about can't distinguish them from flat grinds unless you pull out a straight edge and lay it on the blade. With this kind of setup, most of the slicing or shaving advantage that a hollow has over a flat is absent, but then most of the loss in edge strength or the propensity to bind is absent as well. Some makers prefer this type of geometry if doing a saber grind, as it is much easier to hollow grind a perfectly straight primary shoulder than to flat grind it, at least by hand. Again, this comes down to aesthetics, but aesthetics are not an empty consideration for many, especially as the price of the knife goes up.
All of this said, I do have to talk about the SLUTs---they are not large fixed blades, nor "average" Busses. Hollow grinds do slice well, and I actually like to see that kind of geometry on a knife the size of an Active Duty or Mean Street. Their hollows are wide enough in relation to the width of the blade that they're not going to bind severely even if used as splitting tools which is not really their purpose. They will cut extremely well in normal knife use, and can readily be backed up by their beefier Busse brethren if and when nuclear-level destruction is required.
So there...that's my story and I'm sticking to it.
