I will give you an honest answer, to me, the value is not stagnant:
I own a MM. Would I sell it for 12k?- NO - I really don't have any other hobbies and my bills are paid for except for my house which will be paid for in about 6 years. So, YES, it is worth more than 12k for me because 12k would not pry it from my hands, or any pin combination that equals 12k at this time. It is my favorite pin, in my only hobby.
If I had a house fire and lost it, would I replace it? - NO, I don't have collectibles insurance and the price of a replacement today would be more than I could afford as I bought it when it was affordable to me. So in this scenario, NO it is not worth 12k for me.
If there was a family emergency and I had to come up with lots of money to help my family- then it is worth the most amount that I could get for it in a short amount of time- even if it is significantly less than 12k. Circumstances again make it less valuable to me.
If I won the Powerball Lottery I might be inclined to send one to HEP and install gold trolls and a dragon with fire coming out of his ass, because 12k is 20 seconds of interest on my 600 million. (Before you scoff at my hyperbole, there are some very wealthy people on here and 12k doesn't mean the same to all people.)
Since there are so many variables, and worth is so subjective, and everybody's circumstances different, how would you answer the question without referring to market value?
BTW- 99.99999999999% of the population would not pay 1k for a MM. Does that mean that is its worth less than 1k?
Since I gave you as an honest as can be answer, and I did not see an answer in any of your posts, I am curious:
How much is it worth to you?
If you owned one how much would you sell it for?
If you did not own one, how much would you buy it for?