Pricing and markets will change with time for any commodity for a variety of reasons. Several factors not mentioned with respect to cards and pop reports have not been mentioned in this thread.
1. What percentage of vintage cards have ever been submitted for grading? No one knows but estimates on previous threads here vary greatly. If the majority of the commodity out there is not included in the pop reports, what conclusions can anyone draw from the data?
2. What percentage of vintage cards are cracked out of slabs by purists (sometimes called feelers) and then ultimately resubmitted for grading? Since removing cards from pop reports when slabs are cracked is not done, these cards would appear in pop reports two, three or more times and not necessarily with the same grade. If the highest known example of a card is the 1 of 1 graded 5, is it really better than the one graded 4, the same card from a previous submission.
3. With respect to T206 cards and backs, the various mainstream graders did not initially take backs into consideration. Back specific population reports represent only a percentage (and in some cases a low percentage) of the total cards graded with the same front. If a certain card has 100 graded examples at XYZ, but only 10 of them are Piedmonts, does it make any sense to market an XYZ 6 Piedmont card as a 1 of 1 with none known higher. I think not.
4. I used to follow pop reports to make decisions, but the grading companies will on a whim change their format, such as including different variations such as back info (not including historical data). This can also result in old data disappearing or changing overnight due to a software glitch from an IT guy who doesn't know squat about pop reports being in charge of the changes. Keeping the pop reports accurate seem to be a relatively low priority for the grading companies.
Therefore the arguments made regarding the consumers being more savvy due to increased information resulting in higher prices may be fallacious. I for one have become increasingly more skeptical of pop reports. From a mathematical and scientific point of view, I regard them as junk science.
So there!!!
Having said that, I am happy to welcome the more 'informed" (yet more naive, see above), new collector to the hobby who is willing to pay me
higher prices for my "rare" Polar Bears and forest green Sovereigns.
I'm sure that some of my cards will be perceived as bargains in their eyes.