[mrreality68]

Originally Posted by Eric72

Generally speaking, there are fewer Seaver rookies available for sale at any one time. As such, the competition for Seaver rookies is a bit more spirited among collectors who simply wish to own one.

Both cards are from the late '60s. Both are multi-player cards that feature HOFers. One (Seaver) may be the best pitcher from the 20th Century. The other (Ryan) may be the most popular pitcher from the 20th Century. In a "tale of the tape" that's otherwise relatively close, Seaver's scarcity matters.

As for the prices at higher grades, Ryan's popularity may be a factor. This popularity applies to both the player and the card. Ryan's rookie has been a chase card for 35-40 years. For those into "competitive collecting" it probably makes sense to spend an extra five grand for a one-grade-bump.

Both cards are great cards to have in your collection. They getting 1 of each in whatever the best grade your budget allowed.
As for the why I think it feels like their are always Ryan’s cards available for purchase or auction.