Are some cards too rare for their own good?

[BobC]

And the desirability of the actual issue also plays a big part in the value of such ultra-rare cards. For example, Ty Cobb is easily one of the most recognizable names from the early 20th century amongst ballplayers. His T206 prices have been shooting up in recent years, with the recent find of the several Ty Cobb with Ty Cobb back cards possibly being the penultimate and most publicized find of Cobb cards in recent history. Obviously the value for these is tremendous, coupled with the interest and story of the find and the rarity involved.

However, if you look at Ty Cobb cards and the rarity of issues and tobacco brands, the S74-1 white version silks have Ty Cobb in the issue, same image as appears on his T205 card, and they have one ultra rare tobacco brand that Cobb appears with from Helmar tobacco. There are only two or three Helmar backed Cobb silks known to even exist, which is so much rarer than even Ty Cobb tobacco Cobb cards, yet a Helmar - Cobb silk will go for nowhere near what a Ty Cobb tobacco Cobb T206 would go for.

In this particular instance it is also probable that the silk gets a lower value due to the fact that PSA will not grade them, and thus you don't get the registry crowd interested in the set either.