A person with a coin to sell asked, "Why is it only worth $300 when the book says the value might be $20,000 or more?"
This is not the type of question I enjoy trying to answer. With previous attempts, I've seldom felt the person who asked the question was completely satisfied with my response. Nor was I.
I understand there are good reasons why a coin's state of preservation has a profound influence on value. The reasons must be good because most well informed participants accept them. For as long as I've been involved in the hobby and business it has been this way. To doubt the practices that govern the numismatic marketplace would be like wondering about the teaching of a certain religion and then reaching the simple conclusion that all of its millions of followers can't be wrong. During my fifty or so years of involvement with coin collecting the trend has always been toward greater discrimination based on preservation and grade. I see no reason for this obsession with quality to end any time soon. It's an easy rule to comprehend and remember. Quality is always the primary determiner of value. What I do sometimes question is how these differences in value are calculated. My previous experience is what often makes me wonder about the justification for this continuing trend.
I don't think today's collector is any more discriminating than those who were active thirty, forty or fifty years ago. Some of the finest collections ever assembled were built by numismatists that could detect and appreciate minor differences in quality. Even among collectors of modest means, it was common to encounter some very picky customers. It could be that true discrimination and selectivity was even more prevalent prior to the establishment of grading services. Today's collector can set high standards by simply refusing to purchase anything less than the finest products to come from a grading service. Before this option was available the discriminating collector had to acquire independent knowledge concerning the availability of certain coins to determine when what they were viewing was indeed of exceptional quality and thus worth a premium price.
I think it's fair to say that with the exception of a minimal number of discoveries, hoards and new issues being added to the available supply, the coins the marketplace seems to treasure most were around to be had many years ago. The coins haven't gotten better yet the collector's willingness to pay a significant premium for a slight difference in quality has increased dramatically. This can only be happening because aggressive buyers are confident many future participants will continue this trend. Perhaps the most profitable recycling project in history has been accomplished by the various grading services.
Despite trying to do the right thing and profiting from pleasing the next owner, making a purchase still depends on your opinions concerning the combination of quality and value. Would you be content and pleased to add a coin to your collection, and live with its many faults while paying $300 for it when you could well afford to spend the $20,000+ it might take to buy an obviously superior example? Would owning the $20,000 coin result in far greater satisfaction and enjoyment? These are questions every serious collector seems to always be trying to answer.
Discrimination and an appreciation of quality are not attributes usually acquired by following a trend. Intelligent discrimination often requires knowledge and unbiased investigation. My experience has been there are times when the best value is not found when purchasing the highest quality. In the past, the marketplace has decided some sudden and disappointing adjustments should be made.