As an Admitted Box Collector... I'll take this one...
Believe me, I do understand the attraction of a vintage gun with its original box. What I don't understand is paying huge money for a box you know is not original to a gun, then putting said gun into it, and expecting the price of a gun with its original box. I also don't understand paying a premium for a gun with a box that is clearly not original just to have a box.
Here is my response to a similar comment posted a year or so ago, and to give you a little insight into the mind of a "box collector":
I collect Smith and Wesson Revolvers. And I collect Boxes for Smith and Wesson Revolvers. There is a market price for each separately and when they are paired together and when they are believed to be "100% matching".
* Some of my guns are housed in boxes that number to the gun and may be original to the gun - those are cool and I like them.
* Some of my guns are housed in boxes that do NOT number to the gun - they are cool and I like them too.
* Some of my guns are in boxes with no numbers or identifying marks on them that link them to any specific gun - they also are cool and I like them too.
* Some of my guns have custom aftermarket cases that are specifically made for that gun - they are way way cool and I really like them.
* Some of my guns do not have period correct boxes - so I look for them and pay "market" for them whenever I find them. I also like the hunt for boxes (some OCD desire to put together complete packages, even if they are not "perfect").
* Lastly - some of my boxes for S&W's have no gun in them. I always keep my eyes open for guns to put in them and buy them when I get the chance.
I look at the box different than the features of the gun itself. The boxes were mass produced - not customized to any specific serial numbered gun. The fact that my gun was packaged in box A vs box B that were both produced at the same time in the same factory, is not a huge deal. Sure I like it when the grease pencil/lead pencil number on the bottom is the same as the SN of the gun it contains, BUT the box itself is one of hundreds or thousands. Is there a premium for complete sets that share the same number - yes there is. However, there is also a premium for correct sets where all the numbers do not match and sometimes those premiums are not that different. Particularly on many of the pre-war guns where the SN was written on a small piece of tape on the bottom of the box and often times with the passage of 60+years, that tape is gone, never to be seen again.
I have many guns with boxes and I will never be 100% sure that any of the guns are in the box that they were shipped in from the factory (whether they number or not). I will never represent that to anyone - that is too high of a standard. I generally do not part with my guns, but when I do, whoever purchases them can decide for themselves whether a complete package (appropriately numbered or not) is worth what I am charging. If they believe that it is - they can purchase them. If not, then I'll keep them or sell them to someone else.
BTW - I wish that no one agreed with me, then I could buy all the boxes I find at much cheaper prices...

Apparently, based on prices that I see that is not the case.
My $0.32 (inflation you know...),