Neither the Industrial or the silver badge appear to have cables and many people aren't going to take the effort to find/buy a cable for something that they don't think is worth that much and may have the chance of not working or being in compatible. And the Industrial is missing keycaps. The average person would simply assume that it's broken if it is missing that many parts. And it may be: the rivets might be long gone on that beast, but a bolt mod isn't that hard and the buyer of an Industrial will almost certainly be able to do it, or hire someone to do it for them. And the M122 has a cable, but an odd connector so the seller isn't going to make or buy an adapter for it because that would require research and effort, something many people don't do, especially when they have a lot of things to sell and it may turn out that they spent tons of time on a worthless item. We know it's worth money, but when he listed it, he probably didn't expect nearly what it will go for.
I agree with this concept.
However, if I wanted an industrial, which I kind of do in a vague way, but would not be willing to pay for it, this would be the one to have - extremely early date, heavy plate, black badge, old-style label.
Of course I would completely disassemble it, do a bolt-mod, repair and clean everything, replace caps - all those things are standard procedure for me. I have cables, there is nothing here that I would even blink at as being a deal-killing problem.
A 1390120 would also be a parts donor, I miss the LED indicators. M-122s are parts donors, too, if I was going to settle for a Model M I would obviously opt for the straight-ANSI layout, although I am very fond of Function keys on the left.
In short, if I had loads of money laying around, I would be very interested in this auction.