Hey Don,
#1 - It is not David/Magic Orthodoxy's rarity scale. It was put by a UC member Tom/Magikfingerz.
Secondly, the examples that you gave above are outliers and if you look at rarity scale, you are not going to find any reference what a deck sells in eBay or aftermarket. This rarity scale just tries to differentiate the term "limited' as such, nothing more nothing less.
If it hasn't happened till now in playing card world, should we simply let it go as is or think about what can we do about it? I am not sure if Tom/ Magikfingerz did give this more thought or flesh out more details around it. It resonated with me, and that's the reason I used it.
Hope it gives you a bit more context around it.
David might not have invented it, but he did adopt it, thus making it "his" in that sense.
I understand to some degree what you're saying, but I find using a scale of some kind simply muddies a simple, easy-to-understand number, that being the quantity of decks printed. The scale is vague, the quantity is as precise as you can get.
The scales listed before are in reference to coinage, which in some cases are hundreds of years old. As time passes, there's perhaps uncertainty about how many were made due to lost or destroyed records and how many of those made remain in existence and weren't destroyed, tossed into the bottom of the ocean, etc., hence the use of the scale to get a relative reference as to rarity, allowing one to adequately compare apples to apples, as it were.
Now, while we can't account for every single deck printed and its present state, whether opened, worn-out, destroyed, etc., it's a fairly good gauge of a deck's rarity to simply know how many were printed. Maybe, in a hundred years or so, if people are still collecting playing cards, a scale to at least give an estimate of how many remain in existence would be a good thing to have, but for now, it's not that far-fetched to think that the quantity made is a good reference point for a deck's rarity in the modern-deck collecting world. In fact, I can't think of anything that makes more sense. It's easy to differentiate a deck's rarity based on quantity made, as long as one knows how to count and what numbers are bigger than or smaller than what other numbers; a five-year-old with an adequate education could suss it out.
(Yes, I'm really pushing it here and being a wiseass, but only for the simple reason that as a system for rarity, it couldn't possibly be easier than to know just how many were made rather than some range of possible quantities as represented by a code on a scale. No arbitrary charts to look up or memorize, just a simple number to compare to other numbers, period. It's like the difference between playing poker with a standard deck in the normal way or playing poker with a marked deck and the cards face down, relying on knowing an obscure marking system to know what's in play.)
I think I've exhausted my point here, unless someone has something else to add to the mix that warrants discussion?