* You make a case for the supply side of the economic equation. However, consider the number of examples which retain equal or better condition. Consider the historical significance of the period which this represents. With less hard use, more are found in better overall condition. The three top things which drive collectible prices are condition, condition, and then condition. Rightfully or wrong, Weimar production wear a rap they were not as finely finished as say the early commercials or Kreighoff's. They did not benefit from the better technology in metallurgy and production equipment as say the Mauser pre WWII lugers. They lack the aura of large sweeping documented armed conflicts exciting the imagination as does the wartime examples. Or they do not project the power & adventure of, say, a Navy Luger.
* Also, as you know, there is a demand side as well. Orv Reichert & others wisely point out the seller must find someone who REALLY cares to get the big bucks. To a collector who wants only mint examples of each chamber date or specializes in Weimar Police, this would have appeal.
* Because of the confusing plethora of Post WWI Weimar reworks and the general lack of legitimate, documented collector categories for the Weimar P.08's which prevailed before Jan's Weimar Luger book, these pistols suffered a stigma of possibly being nothing more than clever put togethers. The old collector's adage once was: If you can't definitively ID what a P.08 was, it was probably a "1920's Commercial".
* Fortunately, Jan has organized and categorized the pistols reported from this period. Linking documentation to legitimate identifiable examples has established credibility to these in a wider segment of the population. Raised demand if you will. Some believe the Weimar pistols are the next great sleeper in the Luger stable. Time will tell; but, the market still lags what may be the true and rightful value of these examples relative to all those P.08's which survive.
* Take good care of her, document the verifiable facts which pertain to her, enjoy her for the history and memories won for you by your dad, and someday, "when you get too long in the tooth", pass her onto the next good keeper of history for a fair/reasonable price to assure she has a good home.