Good question. I suspect you normally get your money's worth, though I don't know why super steels like S30V are so expensive once you get past a certain size. For example, why aren't reasonably priced knives with S30V blades available in fixed blades? You'd think it was precious metals instead of steel.
I've never seen the reason to pay as much for a knife as I would a decent handgun, regardless of what the tolerances are like. Yet people drop big bucks all the time for a big name, and in so doing they zip past the point of diminishing marginal returns. One could reasonably ask, would it be better to have two $250 knives than one $500 knife? If the answer is YES, then, would it be better to have two $125 knives than a $250 knife? And you can do this until you settle on your own point of diminishing marginal returns.
Of course the second thing to consider is, am I completely so well off that diminishing returns be damned. If I don't spend the money, my kids will! My problem with C notes is that I tend to get a few and then start thinking about firearms instead of knives. My own personal comfort range is about $85 for a knife, topping off at, say, $125, and this is a folder, of course. I also tend to like longer blades, which puts most of my folding knives into this price range.
I have no doubt that people put a lot of work into five-hundred dollar knives, but it's too much work for my taste and I just love the feel of Zytel. Doesn't scratch, doesn't conduct cold or heat and it's stronger than a bull moose. Still, if a knife had wonderful materials of stag, ivory or finely polished steel that reflect like mirrors, or fine Damascus steel I can see that. Intricate medieval armor has always been something I enjoy looking at.
When I used to ask my uncle open questions, he would reply, "How long is a piece of string?" I suspect that when knife companies write off all their faulty pieces, pay production costs and salaries and such, that the prices we pay are fair, if we shop around. Some companies, though, are now selling only through brick and mortar stores, and there you'll normally see substantial markup. But you'll get services there you won't find through the Internet and hopefully they'll stand behind their products.
I'm getting so frustrated buying through stores in my area. Last week in a Home Depot, every single person I spoke to was from a part of Africa and no one knew anything about the products. Minimum wage, minimum help. And has anyone noticed that you can't buy a decent knife in a Home Depot? I mean, it's a hardware store!
On the plus side, it's difficult to buy a really crummy knife these days if you stick with known brands. That said, the prices of knives are moving up faster than inflation, and that's worrisome. But it's more than just materials you're buying. You can get some Chinese knives made with slave labor that are better than many knives sold in the U.S. 40 years ago, and they're getting better all the time.