Yea, but who buys one random wrench?
Most of us buy wrench sets, not odds and ends.
So, it's sort of useless b/c either you already have one,
or want an entire set (like ratcheting)
Buying one off is silly.
I tend to disagree and I come at this from many angles. I am a tool user, a tool reseller and I also happen to be frugal.
As a tool reseller, I run into at least 2 type of people. One are the folks who have to have nice complete matching sets. I get the impression you are like that. And that is fine for you. Then there is the other folks who want to save money and are willing to wait for the deal and build a set over time.
Being frugal, for my personal tools, I have bought cheap sets early in my career and have replaced them with better quality over time on the cheap. If you were to look at the wrenches on my pegboard at the bench, I probably have at least 10 different brands in SAE. Note, I have at least 2 of each size. I could care less about matching sets, I have been upgrading quality on the cheap for years. Note, I don't wrench full time though it is part of my business. And, I wouldn't call it ********* wrenching where tools had to be top notch to get the job done. Most of the time, a cheap *** Chicrap tool will work. Better quality USA tools make it nicer and that is where I have headed.
One benefit of having different brands is you can identify a wrench size by its looks. Makes it quicker to find the size you want. Especially works well in my road box where the wrenches are stored in a small compartment.
My point being, not all folks buy in sets. Especially expensive sets. Nothing wrong if that is what you want. Not all folks feel that way.
Now as far as a reseller goes. I sell a lot of single wrenches to folks who have lost one. I sell at 50% of retail. Normally works out good for buyer and seller. So I buy a lot of broken sets at auctions.
One thing that sells well for me is big size individual SO wrenches. Over 1 inch. They are darn pricey and guys rarely buy the set that goes up to 2 inch. But they will buy a wrench or 2 every month or so to fill out a set as they become available.
Don't look down on the guy who buys a SO wrench one at a time.