Quoted from flynnibus:

There is a whole side of this hobby that apparently many are oblivious to... but doesn't stop them from letting everyone know it....
Why don't some people checkout this thread... https://pinside.com/pinball/forum/topic/show-off-your-rareprototype-pinball-stuff
And recognize most of that kind of stuff changes hands at unusual prices and generally NOT in the public view.
Not saying the 65k price is right.... but apparently many don't know there is an entirely different type of collector market out there too...

Quoted from pinmister:

People pay a premium for an unmolested barn find car because it is probably a rare car, with lower miles, etc. Again condition and rarity-but not a prototype.
People pay a premium for a handwriting from a famous person because they have a connection with that person or they want something to put on a shelf to show off to others.
It is different with pinball, if the OP invited me into his home and showed off his prototype TZ-I would shrug my shoulders and say "Meh" does not look to be in that good of condition, especially for being an HUO machine-Doh' I would offer him $7000 for a TZ in that shape-I guess I am only $58,000 short. Maybe I can do a go fund me for $58,000 to help a delusional collector buy a prototype TZ? I think the pinball community is way too small to consider the "history of pinball" as a tangible valuable asset.

Quoted from check_switch_26:

There were two or three "first prototypes" made. Two for the programmers (Larry and myself), and I think there was one for the "tagged sample" which was used to verify the Bill of Materials and as a reference for Manufacturing.
There were another 12-15 prototypes made subsequently, and they would have had serial numbers applied before they left the building. They were used for such things as field testing, photo shoot, drop test, ship test, FCC test, ACME Expo, and display pieces for the two largest European distributors at the time. The serial number of my personal game is X970004.
I'm pretty sure that the first two/three did not get serial numbers until they were sold to employees. The game I programmed on was purchased in December 1993, and had the serial number S2720037692, according to the receipt. Beats me what that number means. Those games have the 6-color ring on the clock face. I keep kicking myself for not taking a photograph of it.
As far as I know, that game is still sitting in the basement where I delivered and set it up just before Christmas as a surprise from Santa. It was a gifted it to thank someone who did some work for me.
--Ted
Edited to add: I believe those first 2-3 games had the Clock Millions target added after being first wired. I remember Pat standing next to one of the games as he hand-drilled the holes for the target and insert.

Quoted from gold1:

So it is ok to profit from a seller who does not know the market(reverse rip off) but not to profit by quoting a much higher than market price?Interesting that.