Why are certain pre-war cards so scarce?

[tbob]

Thanks for all the responses, I appreciate them and was interested in reading different theories. As far as the red background E98s go, having seen some shoebox collections come out of the woodwork the last 9-10 years, I don't believe any one color can definitively be said to the toughest color. The problem is that even in population reports from PSA and SGC that the background colors are not separated out so we have no idea which colors are contained in the registry sets.
I still think it is odd that the red background Lajoie is so rare, not only when compared to other Lajoies but also to all cards with their background colors in general but the red background Walsh is so plentiful when compared to the other colors of Walsh cards in the set, although Walsh E98s in general are very tough to find.
Maybe some day we'll know but I think it may be one of the mysteries in life that is never answered.

[tbob]

If anyone reading this thread has a red E98 Lajoie in their collection, I would be interested in hearing about it. Even if it is not for sale, it would be helpful. The only two I have ever seen are the one I had which I sold to Rob D. and is on his webpage and which is shown above and Tim's which he has shared a scan of above also.