I've dealt with a number of collector fields in my day, not just tools. I have a number of general observations.
For one, Lugz is right about the OOAK. I've seen that phenomenon on numerous occasions. Another aspect of this is that just because it's rare does not make it valuable.
Collector communities tend to look at things as if the four walls surrounding their particular field defines the known universe. What I mean is, when looking at the 'forest' overview (as opposed to down in the trees). the communities are much smaller when compared to the general population than many such members imagine. For an item to have exceptional value, it has to appeal to a wide general audience. A giant wooden vise does not have a general appeal--even in this group, there's a diversity of perceived value from thousands to junk. That does not bode well for an astronomical figure in the tens of thousands.
Looking at wikipedia, which anyone can do, the Charles Parker Co. was a huge conglomerate producing a wide variety of products. One of these is art brass, for which it is well known and still highly regarded. The point is that its artistic designs and innovations are what would be featured in a World's Fair or Exhibition. Exhibits showcased exceptional art and innovation. I doubt vises. The item in question is a very conventional-looking vise without any particular artistic or obvious visually innovative distinction. When I think of world's fairs and what is exhibited there, of all the products Parker was known for, I can't imagine they would use this vise as a showpiece display. I bet the seller looked on wiki too and saw the company itself was in two world's fairs. So the vise must have been there too, right? I doubt it--a lot. Here's where that collector field-centric thinking comes in. It's a vise, that's our thing, it must have been at the world's fair. General population thinking...not. It may have been displayed in the sales room or front office of the division that made the vises, and then taken out occasionally to trade shows. But a WORLD'S FAIR? Seller was blowing smoke based on what he found on wiki. Even if it was in a world's fair (not), so what? You see on antiques roadshow all the time how a common item that happened to be in a famous person's house does little to make it valuable.
It's been my experience that a primary consideration of tool collectors is that the item could actually be used for its purpose. Doesn't matter if it is ever used, but the consideration is that it still could be used if one chose. A device that performs a function, especially a mechanical one, in any collector field, must have that quality to command top dollar. Unless, of course, it's a hand forged tool that can be proved came from Washington's carriage house. But there's that general appeal again.
This item is NOT a tool. It is NOT a vise. It is a piece of advertising. As such, one must look at it outside the four walls of tool collecting for it to have any chance at huge dollars. Other than its size, and outside the eyes of the tool collector, it have very little artistic or visual appeal as advertising. Heck, the company name is even just stenciled on the thing, it's not even hand-lettered--if the name is its claim to fame, who knows who even stenciled the name on there? If it were the company that did this stenciling--a company known for its art in metal--they were certainly not prepping it for a world's fair (chuckles). Visually--and outside the eyes of a vise lover--it's actually a pretty lame piece of advertising, almost ugly.
Now comes the next problem. How do you display it? Collectible advertising needs to be displayed to have high value. Who's going to display this thing in a collection of advertising, where it takes up so much floor space, has to be walked around, and blocks the view of whatever's behind it? Maybe a classic car for sure, but tie the display area real estate up on a wooden vise? Real vises are easy to display. So one real factor of value is in the question, "where am I going to display this?" This is why signs are so hot. They're visually appealing, artistic, colorful, reminds folks of days gone by, and....can easily be hung on a wall where it's out of the way while being displayed prominently in all its glory. This vise conjures feelings of what nostalgia? A vise?
None of this is to say it doesn't have value. Of course it does. But when you're talking stratospheric numbers, all the above play into the appraisal formula. It must have a wide appeal to command such numbers. So that someone walking off the street would say from a visually appealing perspective, "Wow, look at how wonderful that is" instead of "what the hell is that thing?" I think it's real-world value is somewhere under $1000. Maybe in an auction with the right buyers present and bidding against one another, I still don't see it reaching even $2000 on a good day.