Quit whining and being defensive dude, particularly as you apparently hit the lotto. Nothing worse than whining from a lotto winner. I don't have an "attitude" about it, I'm shocked. The guys in the K98k collecting community I believe share my sentiments. Thus, if being "shocked" is an attitude, then I guess I have one. That someone would pay $15,000 for a $2,500 (max) 147/1939 is their business I guess, and your bounty; congrats. If the guy posted up in the WTB forum here "I have $5000 burning a hole in my pocket for a nice matching 147 / 1939" he would have been knocked over by guys here trying to sell him nicer ones. Mine is much nicer than that one and I would have knocked him down trying to get it to him for $5,000.
So, revel in your good fortune and enjoy the ride; don't whine, insult, or become defensive over the general (merited) astonishment of you hitting one out of the stadium, out of the parking lot, over the highway, and into an adjacent state. Heck, metaphorically speaking, you yanked this one sufficiently to propel it through the stratosphere and into outer space where it will remain in perpetual orbit around Planet K98k until K98ks start regularly selling for this in the year 2150. Don't get irritated that this is discussed because it is worthy of discussion and was a public sale. Congratulations!