I cannot believe your asking the question. But I think you're really hung up on the rotten moldy pieces I am not a fan of either. Now I see where you are confused because I indeed have not said
why the reduction of moisture is more in a dry aged chunk of premium beef than wet aged.
Maybe my assumptions are wrong. That my concept of wet aging beef is the same as yours. Mine includes letting the meat sit in the fridge in the vac sealed pouch and letting the enzymes do their work (albeit slower) over a period not to exceed 30 or more days, right?
Lets look at a good resource
I will summerize and include these quotes
Facts: Meat Science
Aging of Beef
By F.C.Parrish, Jr., Ph.D.
Department of Animal Science
Iowa State University
I have taken the liberty of pasting some sections for our debate.
"Wet aging is the aging of meat in vacuum bags (usually the middle meats) under refrigerated conditions of 32-34° F. Obviously, humidity and air velocity are not necessary requirements for proper wet aging. Because most beef is vacuum packaged at the site of carcass fabrication (cutting), wet aging is the predominant method of postmortem aging today.
"Dry aging is the traditional process of placing an entire carcass or wholesale cut (without covering or packaging) in a refrigerated room for 21 to 28 days at 32-34 degrees F. and 100-85% relative humidity, with an air velocity of 0.5 to 2.5 m/sec. All three conditions, although varying widely in commercial practice, are extremely important in the proper postmortem aging of carcasses, as well as beef ribs and loins."
There is a third method that uses ultraviolet light to thwart bad bacteria as well.
"Dry and wet aging both result in a similar degree of palatability of rib and loin steaks; however, there can be distinct flavor differences. Meat from vacuum-aged cuts has a more bloody/serumy and metallic flavor, whereas, meat from dry-aging has a more brown-roasted beefy flavor."
I conclude that since a reputable resource has been able to confirm what our Brethren panel has experienced (that dry aged beef is a more concentrated beefy flavor) and that most of the most notable steak houses use the DA process, you my friend, no doubt, have had some BAD dry aged beef that did indeed taste "musty." Either that, or your taste buds are FARKED!!! and I KNOW that cannot be the case.
Did you notice the conclusion that most of the tenderizing process occurs within 7 - 10 days of death!!!!????? Thats a reality bomb. I did not know that until now..... Now furthermore, I and another brethren concentrated (pun sort of intended) on taste, which is mostly from the reduction of moisture Inside the meat.
With that caveat! I say, according to the definition provided herein, by the U of Iowa, that WET aging is within the Vac Pack.... well then the answer to your query is elementary....
In a sealed vaccum pack, no moisture is CAPABLE of being removed from the cut. Where can it go. And as a person who often buys 40 - 50 briskets at a time and refrigerates them for a month or more, I never see a collection of liquid any less or more than it was when I put it in there.
Aging is supposed to affect texture and flavor. Now according to this research the attributes assigned to wet aging are negative (bloody and metallic) and attributes assigned to dry aging are positive (Brown Raosted Beefy flavor). So, they aggree that the flavor profiles of dry aged beef are superior. I win.
However, aging also affects texture and basically most of that gets done IN THE VAC PACK before we get it, unless its from a butcher, in which case it may be dry aged as well... either way, both texture profiles are simular I think they conclude. You win or it could be a draw.
However, since aging does BOTH, a claim that wet aging would be superior is dubios because no credible flavor profile evidence is presented to run contrary to this. So, a claim that dry aging is superior is upheld because is does BOTH while wet aging does only one of the jobs.